0:00:00 > 0:00:00'The question is, why here?'
0:00:25 > 0:00:29'I've dived all over the world, but it's easy to forget
0:00:29 > 0:00:32'there are stunning wildlife dives closer to home.
0:00:32 > 0:00:37'But when two local divers, Robert Walker and Paul Parsons, told me there was
0:00:37 > 0:00:42'a good chance of photographing cuttlefish just offshore here, I was a bit sceptical.'
0:00:42 > 0:00:46So are we expecting to see activity like this if we dive today, or is this quite unique?
0:00:46 > 0:00:49I think we will find some cuttles. I don't know whether we'll quite get
0:00:49 > 0:00:52this activity, cos everything's got to be just right for it,
0:00:52 > 0:00:56but we should be able to find you some cuttlefish, and hopefully mating.
0:01:05 > 0:01:10All this equipment and all this effort, I really hope it's worth it and there are cuttlefish down there.
0:01:11 > 0:01:14Oh, look! There's a cuttlefish!
0:01:14 > 0:01:17Exactly what we wanted to see.
0:01:17 > 0:01:19They're such exotic-looking creatures.
0:01:19 > 0:01:24You'd never imagine to find something like this right here in British waters.
0:01:24 > 0:01:27It's very big. A couple of feet long.
0:01:32 > 0:01:36Cuttlefish are in the same family as squid and octopus.
0:01:38 > 0:01:40Sometimes known as the chameleon of the sea,
0:01:40 > 0:01:43they can change their body colour and patterning
0:01:43 > 0:01:45to mesmerise their prey.
0:01:53 > 0:01:58Oh, gosh! What's he got? Oh, my goodness, he's just grabbed a crab!
0:02:00 > 0:02:01That's amazing.
0:02:01 > 0:02:04Don't think I've seen that before!
0:02:08 > 0:02:14'Cuttlefish have a sharp parrot-like beak and a venomous bite, which will make short work of this crab.'
0:02:17 > 0:02:23'As the sea warms in spring, cuttlefish invade these shallow waters to mate and lay their eggs.
0:02:23 > 0:02:27'This part of the south coast is a real hot spot for them.
0:02:30 > 0:02:36'Male cuttlefish dazzle the smaller females with their striped patterns and flowing tentacles.'
0:02:40 > 0:02:44'They mate head to head, with tentacles entwined.'
0:02:48 > 0:02:52'After mating, the male cuttlefish guards his female as she deposits
0:02:52 > 0:02:56'her eggs, dyed black with ink to deter predators.'
0:02:59 > 0:03:03'This cuttlefish invasion lasts all summer, but, as the water cools,
0:03:03 > 0:03:05'and with their life cycle complete,
0:03:05 > 0:03:07'both males and females die,
0:03:07 > 0:03:10'leaving their bones to be washed up on the beach.'
0:03:12 > 0:03:17Truly amazing - diving this close to the shore
0:03:17 > 0:03:19and seeing these weird, weird creatures.
0:03:19 > 0:03:22That's a pretty incredible dive.
0:03:44 > 0:03:49About 130 miles from Dover is the city of Portsmouth,
0:03:49 > 0:03:54the place with centuries of maritime history,
0:03:54 > 0:04:01a fair proportion of which is connected directly or indirectly with the Royal Navy, down there.
0:04:02 > 0:04:09Her Majesty's Naval Base Portsmouth currently harbours two-thirds of the Navy's surface fleet.
0:04:09 > 0:04:12But the city's proud naval tradition goes back nearly 1,000 years,
0:04:12 > 0:04:16with many decisive military campaigns being launched from here.
0:04:17 > 0:04:21'The question is, why here?'
0:04:21 > 0:04:26Why was Portsmouth chosen above other ports on the south coast to be home of the Royal Navy?
0:04:26 > 0:04:30Archaeologist Mark Horton is in the historic dockyard to find the answer.
0:04:32 > 0:04:36The harbour at Portsmouth has a lot to recommend it, but in many ways
0:04:36 > 0:04:40its trump card has nothing to do with its physical geography
0:04:40 > 0:04:44and everything to do with politics.
0:04:44 > 0:04:48For much of our history, England was at war with her continental neighbours.
0:04:48 > 0:04:52First the French, then the Spanish, and then the Dutch.
0:04:52 > 0:04:57In those battles, it was considered important to have a harbour as close as possible to the enemy.
0:04:57 > 0:05:01For the Spanish wars, that meant Plymouth.
0:05:01 > 0:05:06For fighting the Dutch, Chatham in Kent was best.
0:05:06 > 0:05:11But it was the French wars that were begun by Henry VIII that really made this place important.
0:05:13 > 0:05:20Henry created the Royal Navy in 1525 and decreed that Portsmouth should be its home.
0:05:20 > 0:05:24Through fighting the French 7 times in 290 years,
0:05:24 > 0:05:32Portsmouth grew from 1,000 people in 1545 to over 30,000 in 1800.
0:05:32 > 0:05:39Now the docks were home to 684 ships and were the largest industrial complex in the world.
0:05:39 > 0:05:44'But things for Portsmouth were about to change again.'
0:05:44 > 0:05:47Just listen to that wind to the rigging.
0:05:47 > 0:05:53The Victory, where Nelson defeated the French 200 years ago at the Battle of Trafalgar.
0:05:53 > 0:05:59But ironically, it was that victory against the French that changed the role of Portsmouth for ever.
0:05:59 > 0:06:04From the base where we fought the French, to the place
0:06:04 > 0:06:08where we patrolled the world and fulfilled our imperial ambitions.
0:06:10 > 0:06:14For the next 200 years, Portsmouth's growth was driven more
0:06:14 > 0:06:17by technological invasion than military need.
0:06:19 > 0:06:24'The move from sail to steam in the 19th century saw the biggest expansion.'
0:06:24 > 0:06:29It's the sea just the other side of those somewhat rusty gates.
0:06:29 > 0:06:32This is the number six dry dock, one of around 20 here.
0:06:32 > 0:06:35Portsmouth was not just the centre of the naval operations,
0:06:35 > 0:06:42but also an important dockyard, where ships could be built and comfortably repaired.
0:06:42 > 0:06:46As the ships got larger and larger, so the dry docks themselves had
0:06:46 > 0:06:51to get bigger and bigger to keep pace with technological change.
0:06:51 > 0:06:56In the 21st century, warfare continues to change.
0:06:56 > 0:07:00'So what is the future for our oldest naval base?'
0:07:02 > 0:07:06For the surface navy, the escorts and the aircraft carriers,
0:07:06 > 0:07:07this is where it's all at, yes.
0:07:07 > 0:07:09And does it still work as a harbour?
0:07:09 > 0:07:12Is it suitable for the modern navy?
0:07:12 > 0:07:15Oh, very suitable. There's a large investment programme
0:07:15 > 0:07:20going on to make sure it continues to be suitable, continues to evolve to meet modern requirements.
0:07:20 > 0:07:25Portsmouth is here because of medieval monarchs, Henry VIII and the French.
0:07:25 > 0:07:28I think the reason he chose it was because France was the enemy.
0:07:28 > 0:07:31Today that is not the case.
0:07:31 > 0:07:36Do you think, in 500 years' time, there will be a base here at Portsmouth?
0:07:36 > 0:07:39As long as we've got a navy, it will still be here.