0:00:32 > 0:00:36Blackpool's a resort with global aspirations.
0:00:42 > 0:00:47Its claim, that it's the world's first working class seaside resort.
0:00:50 > 0:00:54But one visitor not here for donkey rides and ice cream
0:00:54 > 0:00:57is Hermione Cockburn. She may be an earth scientist
0:00:57 > 0:01:00but she can't avoid aircraft on this coast.
0:01:02 > 0:01:06The plane just landing behind me never leaves UK airspace.
0:01:06 > 0:01:10It belongs to the Ordnance Survey Flying Unit.
0:01:11 > 0:01:15The Ordnance Survey makes over 150 sorties a year from their base
0:01:15 > 0:01:19in Blackpool. I've come into town to meet Trevor Hilton,
0:01:19 > 0:01:22one of the unit's aerial surveyors.
0:01:22 > 0:01:24So, why Blackpool?
0:01:24 > 0:01:26We map the whole of the country
0:01:26 > 0:01:30and Blackpool's the airport nearest to the centre of Britain.
0:01:30 > 0:01:33Another advantage, as you see, is the lovely weather.
0:01:33 > 0:01:37This stretch of coast gets very good weather, a lot of sunshine,
0:01:37 > 0:01:40so we're not going to be fogbound many days, or stuck on the airport.
0:01:40 > 0:01:44- What are you actually doing up there? - Britain has one of the most
0:01:44 > 0:01:47comprehensive mapping databases in the world, and we update that
0:01:47 > 0:01:50by various means, mainly on the ground,
0:01:50 > 0:01:52but sometimes it's more efficient to do it by air.
0:01:54 > 0:02:00The OS use a super-high resolution camera, a whopping 128 megapixels.
0:02:00 > 0:02:04The photographs are processed at their Southampton HQ.
0:02:04 > 0:02:08But computer software still needs help with detailed variations
0:02:08 > 0:02:14like new housing, roads or coastal changes. These are traced in by hand.
0:02:14 > 0:02:18This then becomes the basis for the standard OS maps we rely on.
0:02:18 > 0:02:23As somebody who's flown the entire coastline of Britain,
0:02:23 > 0:02:26- what's your favourite stretch? - I've a few.
0:02:26 > 0:02:29Probably the west coast of Scotland is my favourite.
0:02:29 > 0:02:33There's some dramatic sights, like the Cullins arising on Skye
0:02:33 > 0:02:35straight out of the sea. Cornwall, as well.
0:02:35 > 0:02:39You can see this clear blue water, the white beaches. Only problem is
0:02:39 > 0:02:43you see these people as specks, and sometimes I wish I was down there
0:02:43 > 0:02:45enjoying myself not stuck up 5,000 feet working.
0:02:47 > 0:02:51Trevor's favourite aerial views are at opposite ends of the country,
0:02:51 > 0:02:54but one of the Ordnance Survey's biggest challenges
0:02:54 > 0:02:56is right on their doorstep.
0:02:56 > 0:02:59Formby Sands, just south of Blackpool,
0:02:59 > 0:03:02is the most dynamic dune system in England.
0:03:02 > 0:03:06Here, whole features have been wiped off the map.
0:03:12 > 0:03:16The OS are going up to photograph Formby's changing coastline,
0:03:16 > 0:03:20but with no spare room in the plane, I've come to meet coastal engineer,
0:03:20 > 0:03:24Paul Wisse, to discover what's happening on the ground.
0:03:24 > 0:03:29Paul, I'd say this is a fairly typical coastal dune system.
0:03:29 > 0:03:33What's striking about this coastline is the speed that it's rolling back.
0:03:33 > 0:03:3725 years ago, this was a caravan park where we're standing.
0:03:37 > 0:03:40So, literally, the dunes have rolled back inland and engulfed...
0:03:40 > 0:03:43Buried beneath us are caravans.
0:03:43 > 0:03:45So do, sometimes, caravans get exhumed?
0:03:45 > 0:03:47There haven't been any yet,
0:03:47 > 0:03:50but in the next couple of years it's very likely that some will...
0:03:50 > 0:03:54- pop out onto the beach.- OK, can you see any evidence of former caravans?
0:03:54 > 0:03:55You can see, just down below us,
0:03:55 > 0:03:59an edge where the foundations of the car park were.
0:03:59 > 0:04:02I got the children, over in the distance, helping pick up
0:04:02 > 0:04:07some of the rubble, which has been washed out by the erosion.
0:04:11 > 0:04:145,000 feet up, Trevor is taking pictures that will show us
0:04:14 > 0:04:17how Formby's dunes are shifting.
0:04:19 > 0:04:22Meanwhile, Paul and his team have taken me out to get
0:04:22 > 0:04:25the perspective from sea level.
0:04:25 > 0:04:29Paul, how fast are the dunes along this coastline changing?
0:04:29 > 0:04:33On average, over the last 100 years, they've eroded by five metres a year.
0:04:33 > 0:04:37The Sefton Coast is mainly made of sand, which is readily moulded
0:04:37 > 0:04:41by the coastal processes, such as the waves, tide, the wind.
0:04:41 > 0:04:44There used to be a cafe on Formby Point,
0:04:44 > 0:04:48- which has been lost to erosion. - Really?- Yeah, got some photos.
0:04:48 > 0:04:52- This was the cafe in 1958.- Right.
0:04:52 > 0:04:55Just three years later, in 1961...
0:04:55 > 0:04:57Oh, my goodness! So that was wave action?
0:04:57 > 0:05:00That's been undermined by the coastal erosion, by the waves.
0:05:00 > 0:05:04- It's just collapsed. - What happened to the cafe?
0:05:04 > 0:05:09According to my GPS, it's right beneath us.
0:05:09 > 0:05:13- Beneath us here? But we're 100 metres or so...- 50 metres off shore.
0:05:13 > 0:05:15AIRCRAFT ENGINE
0:05:15 > 0:05:17Look, there's the plane going over.
0:05:17 > 0:05:20The OS are up there taking our aerial survey.
0:05:20 > 0:05:25You were saying that this coastline has been eroding for 100 years,
0:05:25 > 0:05:27where would the coastline have been back then?
0:05:28 > 0:05:30Keith?
0:05:35 > 0:05:39We're going an awfully long way out!
0:05:40 > 0:05:44- Another 350 metres.- Really?
0:05:44 > 0:05:48So right about where we are now, is where the coast was in 1906.
0:05:48 > 0:05:50That is incredible.
0:05:50 > 0:05:53- We're half a kilometre from the dunes!- Yes.
0:05:55 > 0:06:00That's half a kilometre of Lancashire coast wiped off the map
0:06:00 > 0:06:04in just 100 years. The dramatic erosion here at Formby
0:06:04 > 0:06:09is a combination of the soft sand and high tidal range.
0:06:11 > 0:06:14What I want to know is how the Ordnance Survey's aerial photographs
0:06:14 > 0:06:17capture the history of this eroding coastline.
0:06:20 > 0:06:22- Hi, Trevor!- Hiya!
0:06:22 > 0:06:25So how did you get on? How was Formby Sands from the air?
0:06:25 > 0:06:28We've got a couple of photos here that we took earlier at Formby.
0:06:28 > 0:06:30- Right.- It was a beautiful morning.
0:06:31 > 0:06:37It looks fantastic! You can really see the line of the dunes, there.
0:06:37 > 0:06:40We've got an earlier shot, here, taken back in 1978.
0:06:42 > 0:06:46- You can see here a caravan park. See this bend, here?- Yep.
0:06:46 > 0:06:49- That bend there.- So that's the caravan park that's now
0:06:49 > 0:06:52- completely buried by these dunes? - Indeed, yes.
0:06:52 > 0:06:57How soon before we can expect to see these changes on these kind of maps?
0:06:57 > 0:07:01Every week we're producing new sheets, and individual sheets,
0:07:01 > 0:07:04it will be a number of years depending on rate of change.
0:07:04 > 0:07:09So next time you're on the beach and a plane flies overhead,
0:07:09 > 0:07:12it may be adding you to the map of Britain.
0:07:17 > 0:07:20There are changes happening around our coast
0:07:20 > 0:07:21that don't show up on the map.
0:07:21 > 0:07:25The recent influx of migrant workers is one of them.
0:07:25 > 0:07:28My name's Rafal Sekulski. Everybody calls me Ralf.
0:07:28 > 0:07:33It's shorter. I come from Poland, and I work on Big One.
0:07:32 > 0:07:33SCREAMING
0:07:33 > 0:07:38It's the biggest roller coaster in Europe, 235 feet up,
0:07:38 > 0:07:40up to 85 miles an hour you going on it.
0:07:40 > 0:07:44Part of my job is to make sure that people are safe on Big One.
0:07:44 > 0:07:47And they have fun.
0:07:47 > 0:07:50The first time coming here I didn't really want to go on it,
0:07:50 > 0:07:54cos I really scared of heights, but they pushed me in a train.
0:08:01 > 0:08:04SCREAMING
0:08:05 > 0:08:07I was really scared the first time.
0:08:07 > 0:08:13When I went out of the train my legs were shaking, but now it's OK.
0:08:13 > 0:08:17There's about seven or eight thousand Polish in Blackpool.
0:08:17 > 0:08:21Sometimes when I walk on the prom, every second person speak Polish!
0:08:21 > 0:08:24I just turn around, "oh, my God!" So many of them.
0:08:24 > 0:08:27Sometimes I get a feeling like I'm on Baltic Sea, you know?
0:08:27 > 0:08:31And the English are just foreigners who came abroad!
0:08:31 > 0:08:38# I read the news today, oh boy... #
0:08:38 > 0:08:438,000 Poles in Blackpool, Lancashire - who'd have thought it?