With his dive buddy unconscious on the seabed, Luke Corkill faced a split-second decision: should he risk the bends by bringing her up fast, or face handing a body over to RNLI crews?

Dive safety is a priority for the RNLI's Coastal Safety Team, with over 14 divers losing their lives in the UK and RoI every year. Even with experience and the best of preparations the smallest of incidents can quickly escalate.

That was the case on 26 June 2012, when two divers from the Sussex Dive Club took a routine wreck dive on the Peronne, a sunken cable laying ship 5 miles off the coast of Brixham.

Visibility was a little gloomy but both divers – Luke Corkill, a qualified BSAC Dive Leader for 15 years and his dive buddy Anna Bate – were experienced and able to deal with the conditions.

But as the pair descended to 30m and began to explore the wreck, Anna's fins became entangled with a line on the seabed.

In the struggle to free herself, she disturbed sand and silt, clouding their visibility. As Anna bent down to unpick the line, the regulator on her air tank began to free flow, releasing huge volumes of air – meaning that her air supply would run out very quickly.

‘In the low visibility I wasn’t initially aware that Anna was trapped, or why she couldn’t ascend to the surface. Once I realised what had happened, I gave her my main air supply while I switched to a back-up cylinder,’ Luke says.

Realising that the situation was becoming critical, Luke spent a frantic few minutes working out where Anna was trapped and cutting the tangled line. ‘As with any rescue, there comes a moment where you have to make a choice – I knew I only had a few minutes to get her free, otherwise I was putting myself in considerable danger.’

After cutting her free, he started a controlled buoyant lift – a technique used to safely raise a diver to the surface from depth – with both breathing from Luke’s air supply.

‘Despite my efforts, she lost consciousness and stopped breathing during the first part of the ascent, but I was determined to do all I could to save her.’

For the dive they had just undertaken, an ascent should have taken 7 minutes. Luke brought them to the surface in almost half that time.

‘You train for these sorts of scenarios, but you have to make a split-second decision; I chose to come up quite fast because I knew that was about the only chance Anna had of survival.’

Having reached the surface and raised the alarm, Luke began to fear the worst. ‘I really thought I was bringing a body back.’

Anna’s condition was grave – she had no pulse. Members of the Sussex Dive Club brought her onto the dive boat and gave rescue breaths and cardiac pulmonary resuscitation (CPR).

Meanwhile, Torbay's volunteer lifeboat crew raced to the scene in their all-weather lifeboat with Coxswain Mark Criddle at the helm. Coastguard helicopter support from Rescue 106 was also en route from Portland.

Anna was conscious by the time the lifeboat arrived but Luke and Anna weren’t out of danger yet: both were at risk of decompression sickness (known as ‘the bends’) from their fast ascent. Anna also faced problems associated with secondary drowning due to the water she had ingested.

Torbay Crew Members Dr Alexander Rowe and Nigel Millard boarded the dive boat and transferred the pair to the lifeboat. They then prepared Anna and Luke to be winched into the helicopter and taken to Poole Hospital, in Dorset, for treatment in a specialist decompression chamber. Amazingly, both were released within days.

For their part in the rescue, Luke and Nicholas Taylor, of the Sussex Dive Club, are being awarded Royal Humane Society Testimonials on Vellum. But for Luke it is down to the extraordinary teamwork of Torbay lifeboat volunteers and those on the dive boats that he and Anna are both alive to tell the tale.

‘I just want to say thanks to the RNLI crew who helped us. They were so thorough, and very professional. It was very reassuring to have their calm presence. The efforts of people on the dive boat and the amazing response of the emergency services was also instrumental.

'Every single person played a part,’ adds Luke.