It’s not your typical Monday morning. I’m off the coast of Turkey and climbing into a mini-submarine called Nemo. The British, French and Norwegian team behind the NATO Submarine Rescue System (NSRS) are taking me on a dive just to show what the NSRS can do. It’s an underwater ambulance, a lifeline for submariners if they ever were to get stuck on the ocean bottom.

Nemo is a submarine rescue vehicle or SRV. As she descends it’s not what I expected. It’s hot, noisy, and cramped. I’m travelling with divers from Canada, Turkey and Poland – all keen to experience this too. In the still waters of the Eastern Mediterranean, our descent is calm – but Nemo can still function in waves that are 6 metres high. She can also dive to 600 metres but today’s rescue is just an exercise – part of NATO’s Dynamic Monarch.

We’re more than 100 metres down and this Submarine Rescue Vehicle must mate with a Turkish Submarine - the TCG Burakreis. Nemo creates a seal with the skirt on her underside. The water is drained and then comes the nerve-wracking moment for me. We’re about to open our hatch deep under the ocean… But whilst I am panicking, the crew are not - they have done this many times before.

And they know this Nemo’s capabilities. The hatch opens and then the submarine crew open their hatch too – the Turkish submariners beneath us are delighted to see this process for real. The team behind the NATO Submarine Rescue System hope it will never ever be used.

But if there is a submarine emergency it’s kit like this which will help save submariners lives and get them safely back to the surface. More: Five Things You Didn't Know About Britain's First Nuclear Test