0:00:32 > 0:00:35This time, we're on our way up the east coast
0:00:35 > 0:00:39from Berwick to Aberdeen, via Edinburgh.
0:00:47 > 0:00:54Our journey actually starts in England, where the River Tweed flows through Berwick into the North Sea.
0:00:54 > 0:00:58In the 13th century this was a thriving east coast port.
0:00:58 > 0:01:03Back then England and Scotland fought endlessly over Berwick.
0:01:03 > 0:01:07You'd think that people here would be obsessed with war against the Scots.
0:01:07 > 0:01:08MUSIC: "1812 Overture" by Tchaikovsky
0:01:11 > 0:01:14# Oh, I do like to be beside the seaside... #
0:01:14 > 0:01:20But in fact, the war that everyone talks about nowadays is the one between Berwick...and Russia?!
0:01:21 > 0:01:25Now, I've dug into some unlikely historical goings-on
0:01:25 > 0:01:26from time to time,
0:01:26 > 0:01:29but a war between Berwick and Russia? I don't remember that.
0:01:29 > 0:01:30What's that all about?
0:01:35 > 0:01:39It all goes back to a piece of paper five centuries old.
0:01:39 > 0:01:43I just happen to have here a copy of The Treaty of Perpetual Peace,
0:01:43 > 0:01:46signed over 500 years ago in 1502.
0:01:46 > 0:01:49It was a road map for peace between Scotland and England.
0:01:51 > 0:01:56The ambitiously named Treaty of Perpetual Peace was doomed to fail
0:01:56 > 0:02:00if the bitter arguments about Berwick couldn't be settled.
0:02:01 > 0:02:04Both England and Scotland wanted Berwick...
0:02:04 > 0:02:08so to end the squabbling, neither got it.
0:02:08 > 0:02:13Berwick was made semi-independent, as if it were a separate state in its own right.
0:02:17 > 0:02:24But how did Berwick's special status lead to war with the mighty Russian empire?
0:02:24 > 0:02:29Fresh from the Russian weekend celebrations is Master of Ceremonies Chris Green.
0:02:29 > 0:02:31I'm hoping he can help me figure it all out.
0:02:33 > 0:02:34So what's the score, Chris?
0:02:34 > 0:02:37What is it that the people of Berwick have against the Russians?
0:02:37 > 0:02:40The story is we're still fighting the Crimean War.
0:02:40 > 0:02:44The story goes that when Britain declared war
0:02:44 > 0:02:48against Russia in 1854, Berwick was included in the declaration of war,
0:02:48 > 0:02:51but when it came to the peace in 1856, Berwick was missed off
0:02:51 > 0:02:55and so theoretically Berwick is still fighting the Russians.
0:02:55 > 0:03:00And because Berwick has this bizarre
0:03:00 > 0:03:04semi-independent status from the Treaty of Perpetual Peace,
0:03:04 > 0:03:07it means that having declared war it would have to declare its own peace.
0:03:07 > 0:03:10That's absolutely so, yes.
0:03:10 > 0:03:15Now that sounds like the basis for a fantastic pub quiz question, but is it true?
0:03:15 > 0:03:18Well, I have to say, it is a complete myth.
0:03:18 > 0:03:24It was all sorted out in 1747 and every mention of England after that also includes Berwick-upon-Tweed.
0:03:24 > 0:03:27That was long before we went to war with Russia in 1854.
0:03:27 > 0:03:31But you've done well to keep the myth going as long as you have.
0:03:31 > 0:03:34Yes, and we'd just like to keep it that way, if you don't mind.
0:03:34 > 0:03:37- Never let the facts get in the way of a good story.- Absolutely.
0:03:57 > 0:04:01We've reached the outskirts of Scotland's capital city.
0:04:05 > 0:04:08Edinburgh Castle stands proud of canyon-like grey streets,
0:04:08 > 0:04:14and, towering above it all, a volcanic plug of rock, Arthur's Seat.
0:04:16 > 0:04:20It's up here that you see Edinburgh for what it really is -
0:04:20 > 0:04:23a coastal city, with the docks that helped build it
0:04:23 > 0:04:26only a stone's throw from the city centre.
0:04:27 > 0:04:30The industrial heart of the city is here,
0:04:30 > 0:04:35less than two miles from the Castle, in Edinburgh's twin town of Leith.
0:04:35 > 0:04:37MUSIC: "Lust for Life" by Iggy Pop
0:04:40 > 0:04:45This corner of the city has been known as a blackspot of drugs and deprivation.
0:04:45 > 0:04:48Right now, it's having a bit of a makeover.
0:04:48 > 0:04:53Expensive flats have sprung up beside the Royal Yacht Britannia.
0:04:53 > 0:04:58But Edinburgh once relied on the commerce of these docklands,
0:04:58 > 0:05:03and they helped change the history of the entire British Isles.
0:05:04 > 0:05:08The birth of Edinburgh as Scotland's capital city largely depended on
0:05:08 > 0:05:12the trade flowing through this port, and funnily enough the birth of
0:05:12 > 0:05:14the United Kingdom of Great Britain,
0:05:14 > 0:05:19the Act of Union between Scotland and England, also owed a lot to Leith.
0:05:20 > 0:05:25Back when Scotland was a nation independent of England and Wales,
0:05:25 > 0:05:28it envied the power and wealth of its neighbours.
0:05:28 > 0:05:34To become a great European nation, Scotland needed its own colonies.
0:05:34 > 0:05:41It's July 1698, and those five ships down there are setting sail from Leith to Panama.
0:05:41 > 0:05:46The plan is to establish Scotland's first colony.
0:05:46 > 0:05:52Over 300 years ago, the mission to South America was to be the start of the Scottish Empire.
0:05:55 > 0:05:59For four months, they sailed a 6,000-mile route
0:05:59 > 0:06:04across the Atlantic and Caribbean to the narrow Panama land bridge.
0:06:04 > 0:06:07The colony promised a huge reward.
0:06:07 > 0:06:14If Scotland could control this short cut to the Pacific, they'd outwit the English, Spanish and Dutch traders.
0:06:17 > 0:06:22Unfortunately, the Scots were disastrously ill-prepared for the tropical rainforest.
0:06:22 > 0:06:26The seeds of their failure had been sown back in Leith.
0:06:27 > 0:06:32Here's a list of the things the would-be colonists packed on to their ships.
0:06:32 > 0:06:37Neck ties, bonnets, thousands of wigs, woollen blankets...
0:06:37 > 0:06:40Wigs and woollen blankets for the tropics?
0:06:40 > 0:06:44Just one of the countless mistakes made on this ill-fated adventure.
0:06:47 > 0:06:51Finally, word came back of the expedition.
0:06:51 > 0:06:54And the word was...disaster!
0:06:54 > 0:06:57Two years after the ships had set sail from Leith,
0:06:57 > 0:07:032,000 colonists were dead, their colony abandoned.
0:07:03 > 0:07:05Investors lost nearly everything.
0:07:05 > 0:07:08The failed expedition virtually bankrupted Scotland.
0:07:08 > 0:07:11A financial disaster of such proportions
0:07:11 > 0:07:15that it signalled the end of Scotland as an independent country.
0:07:19 > 0:07:23The English Parliament offered to write off the vast debts.
0:07:23 > 0:07:27An inducement for the Scottish elite to help clinch the greatest deal of
0:07:27 > 0:07:33them all - the union of Scotland and England as one nation.
0:07:35 > 0:07:39Despite widespread protests from ordinary people in Scotland,
0:07:39 > 0:07:43in 1707 the parliaments of England and Scotland were united
0:07:43 > 0:07:46and the United Kingdom of Great Britain was born.
0:07:49 > 0:07:54So a handful of ships leaving this coast for foreign shores
0:07:54 > 0:07:58actually ended up transforming the life of our own isles.
0:08:13 > 0:08:16Big industry's left its mark all along this shoreline.
0:08:27 > 0:08:34Hermione Cockburn explores the centuries-old love affair this coast has had with fossil fuels.
0:08:36 > 0:08:39This is a strange alien landscape,
0:08:39 > 0:08:43dominated by these really odd vast grey lagoons.
0:08:43 > 0:08:45And this stuff...
0:08:46 > 0:08:48..it's very like volcanic ash.
0:08:48 > 0:08:50It's light and crumbly.
0:08:50 > 0:08:54But there aren't any active volcanoes near here.
0:08:54 > 0:08:57This is ash from burning coal - millions of tons of it -
0:08:57 > 0:09:02built up layer upon layer, creating an entire artificial peninsula.
0:09:06 > 0:09:13This peninsula is made of ash from the gigantic Longannet coal-fired power station.
0:09:13 > 0:09:18Over the years, it's coal from this area that fed its furnaces.
0:09:18 > 0:09:21Unlikely though it seems, the power station -
0:09:21 > 0:09:25and the very birth of our coal mining industry -
0:09:25 > 0:09:29is strongly connected to this picturesque little town nearby -
0:09:30 > 0:09:32Culross.
0:09:32 > 0:09:37The whitewashed houses, with their distinctive red roof pantiles,
0:09:37 > 0:09:40give Culross a unique style.
0:09:40 > 0:09:45The transformation started 400 years ago, thanks to fossil fuel.
0:09:49 > 0:09:52The man behind it all was Sir George Bruce.
0:09:52 > 0:09:56He was an extraordinary entrepreneur and he made a lot of money.
0:09:56 > 0:09:58And this was his house.
0:10:09 > 0:10:14Elizabethan businessman Sir George Bruce had his finger in many different pies.
0:10:14 > 0:10:21But what really made his fortune was right on his own shore - coal.
0:10:21 > 0:10:25We don't think of there being a coal industry in the Elizabethan era.
0:10:25 > 0:10:32So how did Sir George Bruce come to pioneer coal mining 400 years ago?
0:10:32 > 0:10:36Local archaeologist Douglas Speirs knows the story.
0:10:36 > 0:10:39Doug, what prompted Sir George Bruce to get involved with coal?
0:10:39 > 0:10:44Well, if we think back to the context of his times, the late 16th century,
0:10:44 > 0:10:46there was one big problem on everybody's mind
0:10:46 > 0:10:49- and that was the fuel crisis. - So hang on a moment...
0:10:49 > 0:10:53an energy crisis is something I think of as a modern-day issue!
0:10:53 > 0:10:55Not something that affected people 400 years ago!
0:10:55 > 0:10:57Absolutely. That's very true.
0:10:57 > 0:11:00Essentially it was wood that powered the country.
0:11:00 > 0:11:05Everything from domestic fires and so on to the fires of industry depended upon wood.
0:11:05 > 0:11:10Quite simply, by the late 16th century, we'd almost completely exhausted our supplies of wood.
0:11:10 > 0:11:13And if there was no wood left, then what was the nation to do for its fuel?
0:11:18 > 0:11:25With most of the forests chopped down, people 400 years ago needed an energy revolution.
0:11:25 > 0:11:29Until Sir George Bruce came along, coal mining was in its infancy.
0:11:29 > 0:11:37Bruce's great leap forward was to follow coal seams deep underground by tunnelling along them.
0:11:37 > 0:11:40But when he began digging at Culross,
0:11:40 > 0:11:44he had no idea that the seam would lead him underwater!
0:11:46 > 0:11:53He tunnelled beneath the sea bed - two centuries before the Industrial Revolution!
0:11:53 > 0:12:00But what's even more incredible is what Bruce did once he'd tunnelled a third of a mile out.
0:12:00 > 0:12:05Below us, in fact, if I take this ranging staff here...
0:12:05 > 0:12:09just about two metres below us, you can feel that's solid stone.
0:12:09 > 0:12:12That's the top of a mineshaft.
0:12:12 > 0:12:19This was a second access point for a mine, which entered the ground just below the castle behind us,
0:12:19 > 0:12:26- dived down following a seam of coal reaching to this extent almost 240 feet below us.- Sounds incredible.
0:12:26 > 0:12:29So he had a tunnel extending from a mineshaft on land,
0:12:29 > 0:12:34tunnelling under the water, and then he sank a vertical shaft 240 feet?
0:12:34 > 0:12:36That's exactly what he did here.
0:12:37 > 0:12:42The offshore vertical shaft was a radical innovation.
0:12:42 > 0:12:46It meant Bruce's coal miners could breathe fresh air.
0:12:46 > 0:12:50What would have been here, what would it have been like 400 years ago?
0:12:50 > 0:12:54If you imagine something of the nature almost of a chimney,
0:12:54 > 0:12:57a gigantic great chimney, 50 feet in diameter,
0:12:57 > 0:13:02coming out of the water here and going up perhaps 30 or more feet.
0:13:02 > 0:13:05Straight up above us, this towering great chimney
0:13:05 > 0:13:08with the coal coming directly up onto the platform.
0:13:08 > 0:13:11Ships could come alongside, just as we are floating here in this boat,
0:13:11 > 0:13:13and they could load the coal directly,
0:13:13 > 0:13:16and sail off and take it off to the market places.
0:13:16 > 0:13:19So it was really a bit like an offshore oil platform?
0:13:19 > 0:13:24This is one of the greatest technological achievements of late-medieval Europe.
0:13:24 > 0:13:29And that the project was even contemplated, let alone put into practice, is just mind-boggling.
0:13:30 > 0:13:35The ships that took Culross's coal to the continent brought back
0:13:35 > 0:13:40red roof pantiles from Holland as ballast for the journey home.
0:13:40 > 0:13:44So Culross's unique look comes from its coal trade.
0:13:44 > 0:13:51Thanks to Bruce's industry, for a while Culross was larger and wealthier than Glasgow.
0:13:51 > 0:13:57And his coal technology helped launch the fuel that would dominate Britain for centuries.
0:14:15 > 0:14:19A few miles along the estuary is Rosyth dockyard.
0:14:19 > 0:14:24This is where nuclear submarines are held as they wait to be decommissioned.
0:14:24 > 0:14:32During the two world wars, it was one of Britain's key naval bases, and a tempting target for attack.
0:14:33 > 0:14:36The small islands guarding the inner Firth of Forth
0:14:36 > 0:14:38were a first line of defence.
0:14:45 > 0:14:51A major threat was German submarines, U-boats, gliding unseen up the Firth.
0:14:54 > 0:14:57The battle to detect and deter German U-boats
0:14:57 > 0:15:01led to some extraordinary innovations on this coast.
0:15:01 > 0:15:03Take a closer look at that island over there.
0:15:07 > 0:15:11From one angle, Inchmickery island looks harmless enough.
0:15:11 > 0:15:14But 60 years ago, a U-boat attacking at twilight
0:15:14 > 0:15:17might have confused the island's profile
0:15:17 > 0:15:19for a battleship, and turned tail.
0:15:20 > 0:15:23Local legend says the island's fortifications
0:15:23 > 0:15:29were deliberately built like a battleship's superstructure to scare away the enemy.
0:15:29 > 0:15:34But when it came to schemes for foiling the U-boats, truth is stranger than legend.
0:15:34 > 0:15:40The First World War gave rise to some bizarre plans for detecting German U-boats.
0:15:40 > 0:15:45But perhaps the most outlandish began development here in Scotland - not by the Royal Navy,
0:15:45 > 0:15:51but by a member of the public. And now, 90 years on, we're going to give it another go.
0:15:53 > 0:15:58With some help from model-maker John Riddell and history buff Diana Maxwell,
0:15:58 > 0:16:04we're going to re-create the 90-year-old scientific trials of one Thomas Mills,
0:16:04 > 0:16:08inventor, and would-be scourge of the early U-boats.
0:16:09 > 0:16:14Now, I've got the secret ingredient for hunting submarines.
0:16:14 > 0:16:16I see you've got the model.
0:16:16 > 0:16:19No wonder they're so hard to find if that's all the size they are!
0:16:19 > 0:16:22How much of a problem were the U-boats?
0:16:22 > 0:16:25Well, it was an absolutely enormous threat in the First World War,
0:16:25 > 0:16:29because they were locating and sinking
0:16:29 > 0:16:31one out of four of the merchant fleet
0:16:31 > 0:16:36that were supplying Britain with food, and it could have been that Britain would have starved.
0:16:38 > 0:16:41At the height of the First World War,
0:16:41 > 0:16:43German U-boats were inflicting
0:16:43 > 0:16:45terrible losses on our merchant shipping.
0:16:51 > 0:16:55With no method of detecting the subs, they seemed unstoppable.
0:16:56 > 0:16:57Food imports dwindled.
0:16:59 > 0:17:04The U-boats' stranglehold threatened to cost Britain the war.
0:17:04 > 0:17:07The Government were so desperate, they invited suggestions
0:17:07 > 0:17:12from the public on how to spot and sink the U-boats.
0:17:12 > 0:17:17Millionaire businessman Thomas Mills threw his hat, and his money, into the ring.
0:17:18 > 0:17:24For the first part of his ingenious plan, he set about towing model U-boats around the coast.
0:17:25 > 0:17:29The wartime technique for detecting U-boats was fantastically simple.
0:17:29 > 0:17:31It really was amazing.
0:17:31 > 0:17:36Our version of the experiment relies on a rather special secret ingredient...
0:17:40 > 0:17:42..the humble sardine.
0:17:42 > 0:17:47The experiment begins by stuffing the sardines into our model U-boat.
0:17:48 > 0:17:51Eugh, just bits of it going everywhere!
0:17:51 > 0:17:53Yeah, war's a filthy business, Diana!
0:17:54 > 0:18:01The idea is that if you were to trail a model like this full of bait up and down the coast often enough,
0:18:01 > 0:18:05the gulls in the area would come to associate the sight of a periscope
0:18:05 > 0:18:06with the chance of food.
0:18:07 > 0:18:13U-boats were hard to detect, because only their periscopes showed above water.
0:18:13 > 0:18:15With his model U-boats, Mills hoped, over many runs,
0:18:15 > 0:18:20to teach gulls that the sight of a periscope meant the promise of food.
0:18:21 > 0:18:25So, gulls would see a periscope, think it's time for lunch,
0:18:25 > 0:18:29and flock around it - just like they do with fishing boats -
0:18:29 > 0:18:33and, hey presto, they'd give away the U-boat's position.
0:18:44 > 0:18:47For his scheme to work, you need gulls.
0:18:48 > 0:18:54We're waiting for them to start flocking around our model stuffed with sardines.
0:18:54 > 0:18:58But we've hit a rather serious snag - no birds!
0:18:58 > 0:19:02MUSIC: "Air on the G String" by JS Bach, from Hamlet commercials
0:19:02 > 0:19:08I'm beginning to get a sense of why the Ministry of Defence didn't take this one particularly seriously...
0:19:11 > 0:19:15Just how blatant an invitation do these critters need?
0:19:16 > 0:19:19There's not a gull for a hundred miles.
0:19:19 > 0:19:21Well...not entirely true.
0:19:21 > 0:19:23There's one.
0:19:23 > 0:19:27There's more where that came from, you miserable little swine! Tell your friends.
0:19:28 > 0:19:34It seems all we've established is that gulls don't like blustery winter weather -
0:19:34 > 0:19:38a fundamental flaw if you're trying to train them to spot periscopes.
0:19:40 > 0:19:43Right, Diana - plan B.
0:19:43 > 0:19:47- We'll have to attract them. Throw in everything you've got. - Fish-wise?- Yeah.
0:19:48 > 0:19:50Look, there's a SEAL on the case.
0:19:50 > 0:19:52DIANA LAUGHS
0:19:53 > 0:19:56The whole thing could take a different turn.
0:19:58 > 0:20:04I think we'd have to concede, Diana, that that experiment returned a negative result.
0:20:04 > 0:20:05Good fun, anyway!
0:20:09 > 0:20:14As for the inventor, Thomas Mills, he was refused Navy support for his experiments,
0:20:14 > 0:20:19but went on believing that his gulls method would defeat the U-boat.
0:20:19 > 0:20:26His conviction might seem a little ridiculous now, but it's a sign of just how desperate Britain was.
0:20:31 > 0:20:38As Mills was teaching gulls to look for U-boats, sailors were being taught to LISTEN for them.
0:20:40 > 0:20:46At the Naval Research base in nearby Aberdour, underwater microphones were developed during the First World War.
0:20:47 > 0:20:51Thousands of operators were trained to recognise the engine noise
0:20:51 > 0:20:56of approaching U-boats - technology that paved the way for sonar.
0:20:56 > 0:21:01In the end, it was safety in numbers that protected our shipping from the U-boats.
0:21:01 > 0:21:04Travelling in convoys meant that ships
0:21:04 > 0:21:08could be more easily defended by armed escorts...
0:21:08 > 0:21:10gulls or no gulls.
0:21:19 > 0:21:23The Firth of Tay marks our turning point around the corner of Fife.
0:21:24 > 0:21:27The Tay's the mightiest river in Britain,
0:21:27 > 0:21:31spewing as much water into the sea as the Thames and Severn put together.
0:21:37 > 0:21:42Building bridges across this formidable barrier was a huge challenge to 19th-century engineers.
0:21:48 > 0:21:52The train line crosses over a bridge with a sturdy Victorian feel.
0:21:53 > 0:21:59But look closely beside the base of the pillars, and you'll see a line of curious brick platforms...
0:22:01 > 0:22:05..evidence there was once another bridge...
0:22:07 > 0:22:13..a state-of-the-art engineering marvel, once the world's longest railway bridge.
0:22:20 > 0:22:26But on the night of December 28th, 1879, it collapsed as a train was crossing.
0:22:26 > 0:22:3075 people died. There were no survivors.
0:22:31 > 0:22:35Shoddy construction, poor maintenance and bad ironwork
0:22:35 > 0:22:37have been blamed for the Tay Bridge disaster,
0:22:37 > 0:22:42which still ranks as one of Britain's worst rail tragedies.
0:22:43 > 0:22:46Nearly 130 years later,
0:22:46 > 0:22:51the brick foundations of the old pillars remain as an eerie memorial.
0:22:57 > 0:23:04The fishing town of Arbroath gives its name to a famous hot-smoked haddock, the Arbroath smokie.
0:23:06 > 0:23:08But it's actually in Auchmithie,
0:23:08 > 0:23:12a little village nearby, that smokies were invented.
0:23:15 > 0:23:20Champagne, Gorgonzola, and the Arbroath smokie -
0:23:20 > 0:23:23all in the premier league of delicacies.
0:23:23 > 0:23:25The Arbroath smokie joined the elite club
0:23:25 > 0:23:29when it won the sought-after Protected Geographical Indication
0:23:29 > 0:23:31under European law.
0:23:31 > 0:23:34The EU says, if it ain't made within five miles of Arbroath,
0:23:34 > 0:23:36it ain't a genuine smokie.
0:23:38 > 0:23:42The man who fought for the European law and won is Robert Spink.
0:23:42 > 0:23:48His son Iain smokes smokies the way that makes them worthy of the name.
0:23:49 > 0:23:51Right then, what stage are we at?
0:23:51 > 0:23:53The fire's lit now.
0:23:53 > 0:23:55We're ready to go to put the fish on... OK?
0:23:57 > 0:24:02The traditional method uses a combination of hardwood smoke and dense steam
0:24:02 > 0:24:05to cook the haddock for just the right length of time.
0:24:07 > 0:24:14Why did you go the lengths of getting the might of European law behind the smokie?
0:24:14 > 0:24:18I discovered that Arbroath smokies were being made all over the place,
0:24:18 > 0:24:22out as far... From Cornwall as far north as Aberdeen, you know.
0:24:22 > 0:24:25If people's first experience of the smokie
0:24:25 > 0:24:29is what they've found in a supermarket in Manchester - a poor imitation -
0:24:29 > 0:24:33they'll say, "If that's a smokie, you can keep it." I said, I'm going to do something about that.
0:24:33 > 0:24:37- You really care about this, don't you?- I'm passionate about it.
0:24:37 > 0:24:39It's something I've been involved in all my life.
0:24:39 > 0:24:43I see the smokie as going far beyond just a fish product -
0:24:43 > 0:24:48it's something which is important to the area and gives identity to the area.
0:24:48 > 0:24:50Identity is very important to any area -
0:24:50 > 0:24:52if I buy a Melton Mowbray pork pie,
0:24:52 > 0:24:54I want it to have been made in Melton Mowbray.
0:24:54 > 0:24:57I know what it tastes like, and it's lovely -
0:24:57 > 0:25:00and that's how I want people to think of a smokie, in the same way.
0:25:04 > 0:25:06Is that us, then?
0:25:06 > 0:25:11- That's them ready. Looking good. - That's been about 40 minutes?
0:25:11 > 0:25:15Yep, more or less 40 minutes cooking there. Would you care to try one?
0:25:15 > 0:25:18- If your hands are flameproof! - Absolutely.
0:25:18 > 0:25:22- Once they're hot like this, they're quite easy to bone.- Look at that!
0:25:22 > 0:25:24- Look at the white flesh!- Absolutely.
0:25:24 > 0:25:28That's how you know a good fresh smokie. It's pure white inside.
0:25:32 > 0:25:35I've had smokies before, but that is a particularly good example.
0:25:35 > 0:25:38They're quite different fresh from the fire.
0:25:38 > 0:25:40To me, that's as good as fish gets.
0:25:52 > 0:25:55Mile after mile of coastal cliffs.
0:25:55 > 0:25:59We're on the home straight, the northeast edge of Scotland.
0:26:01 > 0:26:06The dramatic rock formation at Dunnottar was adapted to build a mighty castle.
0:26:06 > 0:26:10A fort is thought to have existed here for well over a thousand years.
0:26:15 > 0:26:21After this vast stretch of wild coastline, we've arrived at a great coastal city - Aberdeen.
0:26:28 > 0:26:32The sheer number of ships coming and going make this one of the busiest ports in Britain.
0:26:37 > 0:26:40Day and night, these ships service oil and gas installations
0:26:40 > 0:26:44hundreds of miles out in the North Sea.
0:26:47 > 0:26:51Not every bit of the coast is picture-postcard pretty.
0:26:51 > 0:26:56Some of it's been put to hard work - and nowhere more so than here at Aberdeen.
0:26:56 > 0:27:00But this is another part of the story, and it's vital to the nation.
0:27:10 > 0:27:17The UK's North Sea oil and gas industry generates around £10 billion a year in tax revenues.
0:27:19 > 0:27:24Oil has transformed Aberdeen from fishing port to the Dallas of the North.
0:27:25 > 0:27:30It might not look like it now, but North Sea oil production is in decline.
0:27:30 > 0:27:34In 50 years' time, all of this might look very different.
0:27:34 > 0:27:40Who knows? Maybe Aberdeen will go the same way as Berwick-upon-Tweed, where I started this journey -
0:27:40 > 0:27:44a port once vital to the economies of Scotland and England,
0:27:44 > 0:27:46now trading on tourism.
0:28:03 > 0:28:05Subtitles by Red Bee Media Ltd
0:28:05 > 0:28:07E-mail subtitling@bbc.co.uk