BRITAIN’S SECRET SEAS has been the realisation of a dream, and now that it’s being seen
by millions (it felt odd for me to miss watching the second episode because I was in Greenland), I can enjoy reflecting on some of my favourite moments:

Garvie Island is just offshore at Cape Wrath, Scotland’s most north-westerly point. For the past 100 years, it’s been the bull’s eye of a military bombing range. It’s the only place in Europe where British and NATO forces can drop 1000lb bombs.
The sheer amount of ordnance dropped on the island every year means that some bombs and rockets inevitably miss or fail to explode. That makes it a busy workplace, and an ideal training ground for ordnance-disposal divers.
The dive team based at Cape Wrath are the Royal Navy Explosive Ordnance Disposal (EOD) divers, Northern Diver Group, and I was delighted to be able to join them. At first the plan was for me to accompany the divers and report on their work, but luckily I still have my explosives-handling qualifications from work in the Middle East and Antarctica, which meant that I could be hands-on, help search for bombs and rig the explosive charges and fuses.
A tricky part was that the EOD divers use custom-designed rebreathers with very few metal components – the cylinders are Kevlar/carbon and the solenoids don’t even “click”. They are very lightweight, and look fabulous!
The reason for the special design is that some of those 1000lb bombs are activated by sound and the presence of metal. So I couldn’t use my own rebreather, and to keep things simple we decided that the crew and I would use open circuit and try to find those bombs that weren’t sound-activated.
The waters around Garvie Island are pristine, and big surges added to the great sense of energy of the area.
I followed my dive buddy Ginge through the kelp beds. I thought the live bombs would be easy to spot, but because of the dense weed you really have to work to find them.
When we came across that first one, I stopped dead in my tracks. How often do you swim up to a live 1000lb bomb
Ginge checked it out and confirmed that it was not sound-activated, so I could get in close. The surge was a problem in rigging our marker buoy, so the only way for me to do it was to straddle the bomb and fix the line with both hands.
We surfaced, collected our explosive charge and descended again. The only way I could operate was to resume my straddling position. I know that I was in no more danger than if I had been just next to the bomb, but straddling these things always made me feel more exposed.
Once we had the charge in place, I remember looking around at the beautiful thriving life near the bomb and thinking what a lovely place this is – but not for long!
Back on the RIB, we collected our floating end of the detonator, connected it to the firing mechanism and set it going. As we were about to move off a safe distance, I thought of those times when outboards become the engines from hell and just don’t start. I also thought of the life down there and what was about to happen to it.
But what is amazing is that the marine life and sea birds in the area are thriving. It seems that because people are not allowed there, the wildlife thrives.
Could it be that the best way of protecting wildlife is to bomb it regularly

I was looking forward to the scallop story. I love to dive for them and eat them fresh on the boat, and I thought it would be a simple story to tell. We have a massive overfishing problem globally, and we could bring that story to life by looking at our scallop industry.
Telling the underwater story was harder than expected, however, because of the poor vis. On one dive it was so bad that I couldn’t see Gavin, the underwater cameraman.
So I collected scallops anyway, and delivered the factual content to the camera light as I cruised along.
On the way up, I found that I had actually been speaking through the brown murk to a torch belonging to Stuart, our camera assistant!
Interviewing the scallop fishermen was also much harder than I expected.
If you want to make yourself a target, there’s no better way than to arrive at a fish-market with a camera crew!
The fishermen I met were great, however, and I feel we did a good job of showing a part of the dredging industry and the challenges we all face. How do we keep traditional family-run fishing viable
Our dives in Lyme Bay showed the damage indiscriminate dredging does to our sea habitat. Diver-caught scallops are much more sustainable – but they cost about 10 times more than dredged ones. And our appetite for them is so great that we inevitably keep dredging.

A dolphin autopsy was a perfect way to explain how and why dolphins get washed up on our beaches. We couldn’t include the whole event in the final edit, of course, so here’s the full story:
“You’ve just cut his penis off,” said Andrew. I had to lay the scalpel down for a moment and apologise to the beautiful young dolphin on the table.
I don’t suffer from anthropomorphism, but cutting off its penis just stopped me in my tracks.
Each year around 160 whales, seals, porpoises and dolphins are washed up on Scottish beaches, and the dedicated team at the Scottish Agricultural College investigate their deaths.
Large whales have to be autopsied on the beach, and the team has to work fast, because whales can spontaneously explode as they decompose.
Smaller mammals, such as the emasculated specimen on my bench, can be transported to the laboratory for a comprehensive post mortem.
Andrew had prepared me well for this gory work, and I was wearing full waterproofs, Wellington boots and two sets of gloves, including a knife-proof one for my left hand.
He quickly identified the dolphin as a young male bottlenose, found dead on a north-western beach. We recorded his initial observations including weight (60kg) and length (65cm), and noted that he had some signs of a relatively harmless pox on his back, along with scarring at the base of his fin.
His flippers and sides bore sets of regular scars like small rake-marks. These puzzled me until Andrew lined up a dolphin jaw to the scratches and we could see that these were dolphin tooth-marks, apparently a sign of quite normal behaviour. We could see plenty of evidence of birds having pecked at the skin on the beach, too.
I was admiring the iconic curve of the back when Andrew pointed out that dolphins normally maintain this shape only while alive. I felt along the spine, and it was indeed bent.
We hoped our post mortem would shed light on this apparent deformity.
My scalpel cut easily through the thick blubber, and I removed a large slab from the left side (along with his penis, unfortunately) to reveal the innermost wonders.
Unpleasant, of course – one would have to be mad to enjoy cutting up one of the Earth’s most beautiful creatures. Yet, strange to say, it was fantastic.
As we delved deeper, the major organs appeared normal. Andrew held up the windpipe and lungs. The right lung was heavy and squashed because the dolphin had been lying on his right side.
We celebrated his ability to dive deep by measuring the chest capacity compared to mine. I was surprised to learn that the dolphin’s two kidneys have the capacity of 1000 of our kidneys, so that they can process sea water.
The heart and liver looked huge. As we removed the organs Andrew pronounced them all to be apparently normal.
I ran my hands across the ribs to check for any damage, and with nothing unusual to record we used big industrial shears to cut the ribs from the backbone.
I removed everything that Andrew would let me remove, while he, understandably, tackled the more delicate sections such as the adrenal glands (not swollen, which would have indicated high levels of stress), the testes, the spleen and the head, which went into a vice to be hack-sawed open so that the brain could be flopped into a bowl on the floor.
Aside from a lurking smell of death there were no extra-unpleasant smells with which to contend. There was a lot of blood, but we washed this easily down the drain on my bench.
Finally, we could see the spine. It had a massive deformity, almost a U-bend, beginning just behind his fin. This is what had given our dolphin that “normal swimming” appearance.
As I began cutting sections of the organs into small samples and collected blood and urine for the laboratory tests, washed down the bench and tidied up the scalpels and heavy tools, I felt that my unique and privileged experience had become a cold technical exercise, part of a routine.
But Andrew had now formed a hypothesis that brought my beautiful little dolphin’s short life into perspective and, in a way, back to life.
The dolphin had been born with a spinal deformity. It was no hindrance while he was swimming and feeding from his mother, but when it came time to fend for himself, he couldn’t keep up with the pod.
As a relatively slow swimmer, he couldn’t catch enough food to maintain strength and grow properly, so when he got into trouble in shallow waters, he couldn’t get out of it. He had been washed up alive, but died after some time on the beach.
From a human perspective this looks to be a tough outcome, but his early demise could have been worse.
Andrew told me that it’s not uncommon for young dolphins to be repeatedly attacked by adults, with a group of males separating a calf from its mother before ramming it and holding it under water.
Injuries from such attacks are often fatal. They include rib fractures, massive organ damage, even spinal deformities similar to the one we had discovered.
This behaviour is a long way from our smiling, companionable and heroic friend who joins us at sea, plays in our bow wave and participates in dolphin-assisted therapy the world over.

I laughed when I received the script notes. The idea is a great one – as divers, we see fish hanging around in loose, relaxed shoals, then as soon as they are threatened they form into organised schools. To begin to understand why and how they do this, it was decided that I would dive a wreck off the East Coast.
The script mentioned me diving in clear water with shoals of fish inside a shipwreck, with the sun glinting off their sides. I would swim towards the shoal, and as they identified me as a predator they would form into a school and shoot off with the sun shining on them – a living marine piece of artwork.
I read this on a gruesome wet and windy day and, as I packed my gear for Bridlington, I didn’t think we stood a chance. But our skipper said that the visibility on the east coast had been superb – and my dives were brilliant.
As I swam around, under and in the wreckage with those shoals of fish, I reflected on our great East Coast diving and the power of Sophie, our marvellous Series Producer, who had obviously made the fish read the script!

Partway through making the series, there was a legitimate concern that we would need to explain the loss of colour as we go deeper, particularly as we sometimes used lights and at other times worked in natural light.
The idea was for me to carry a colour chart on a couple of dives and refer to this as a reference at the right moment.
But of course, this is complicated to film, because we had to organise the lights-on, lights-off moments, and cope with the impossibility of me trying to appear natural while swimming around with an A4-sized plastic colour chart, just casually bringing it in on an underwater conversation.
By some kind of miracle, the only sequence that was lost was this one.
We replaced it with Tooni Mahto and me speaking about colour on one of our St Abbs dives.

I was super-keen to make our diving look easy and fun as far as possible.
The less technical clutter the better; I wanted to encourage more people into the water.
The beautiful seals at the Farne Islands offered a great way to engage the public. We could tell the celebratory story of the thriving grey seals in a wonderful setting, and needed nothing technical beyond shallow-water open-circuit or snorkelling gear.
But it got complicated when we thought about describing the way seals are such great breath-holders. So we came up with the idea of asking world-class freediver Emma Farrell to join us, so that I could make the comparisons between humans and seals.
We decided to use ordinary balloons to demonstrate our lungs at depth.
I thought this would be simple.
You’re way ahead of me here, but the complications of diving at 17m with balloons of various sizes had not dawned on me. My dive profiles were pretty rotten as I tried to demonstrate, talk, keep up with Emma, handle balloons, constantly sort out buoyancy and stop myself being seasick in the surging weed.
You might think that would be quite enough creativity on my part, but after surviving the balloon dives I thought we could do a great demonstration of the Mammalian Dive Reflex.
I’d done this before by putting my head in cold water before measuring my pulse slowing down. It had been another very long day at sea, and I did detect a bit of reluctance in the crew, but I was all fired up.
We filled one of the boat’s fire-buckets with sea water and ice; I strapped on the heart-rate monitor and stuck my head in. I hadn’t actually prepared myself properly, so I had to work really hard to keep my head in that bucket – with the camera rolling,
it would have been too embarrassing to hold my breath for only a few seconds.
I hung in there until the bitter end and came out of the bucket gasping, only to find out that there was a sound problem. I dried off, and back in I went.
It worked a treat, and my heart rate went down fine, but again there was a technical problem. So I went for it again, and again.
It was only after about six times that I realised that the crew had had enough, and were getting their own back!

If we’re very lucky, every once in a while we do a piece of work or activity that makes us want to just stop right there.
This happened to me when I made the official voiceover recording of Captain Scott’s iconic South Pole diaries at the British Library. I spent days in its recording studio, and when we had finished we were in floods of tears.
I walked out onto Euston Road and thought: “That’s it. This is the finest piece of work I’ve ever been involved with. I must find a way to stop right now.”
I hadn’t had that feeling since, and then I came to the end of Britain’s Secret Seas. I feel exactly the same – it’s a British diver’s dream come true.
The series could not have been made without the support of the British diving community – thank you! It was great to be diving with Tooni and Frank Pope, and with luck we’ll do a lot more.
And along with our great BBC team, I’m in the thick of planning more diving programmes. There is no chance of stopping!

Britain’s Secret Seas, Sundays at 8pm on BBC2.