As a flickering torch illuminated the pitch-black cave, the first voice heard by the rake-thin boys perched on a ledge in their football kit was that of intrepid Briton John Volanthen.
‘How many of you?’ asked the mild-mannered 47-year-old from Bristol, who has a day job as an IT consultant and runs marathons in his spare time.
‘Thirteen,’ came the answer. ‘Thirteen? Brilliant,’ said Mr Volanthen.
With him was Richard Stanton, 56, a retired fireman from Coventry.
The two highly experienced British volunteer divers who helped to find the trapped boys and their coach have a history of difficult rescues around the world, but even by their heroic standards this must surely count as their crowning achievement.
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British cave divers Richard Stanton (left), Robert Harper (centre) and John Volanthen (right) arrive at Khun Nam Nang Non Forest Park near the Tham Luang cave on June 27
They were specifically called upon by the Thai authorities to join the vast search due to their expertise.
They have well-established reputations as being among the best cave rescuers in the world and the British Cave Rescue Council has even hailed them as ‘The A-Team of cave rescue’.
Cool as cucumbers, they have gone about their work single-mindedly and with absolute professionalism.
‘We’ve got a job to do,’ was all Mr Volanthen would say to reporters when he first entered the cave.
He started caving as a Scout, then progressed to the more dangerous pastime of cave-diving, where, he says, safety depends on remaining relaxed.
British divers Rick Stanton (right) and John Volanthen (left) were the first to reach twelve trapped schoolboy footballers in the waters of the cave system in Tham Luang, Thailand.
Alive: The frightened youngsters were huddled together when the rescue team discovered them trapped in the flooded cave
‘Underwater, things happen slowly,’ he once said.
‘Panic and adrenaline are great in certain situations but not in cave-diving. What you want is nice and boring. If something goes wrong 10 kilometres down an underwater tunnel, you usually have until your air runs out to find a solution or make your peace.’
Mr Stanton, known as Rick and described by friends as ‘quiet and humble’, has modestly described cave-diving as only a ‘hobby’, which he started at the age of 18.
The pair have often worked together. In 2004, they set a new British cave diving depth record after discovering new caverns and passages at Wookey Hole in Somerset.
They also developed the special equipment they are using in Thailand – a modified ‘rebreather unit’ to enable them to stay under water longer – during exploratory dives at Wookey Hole.
Such units add oxygen to exhaled air to recycle it and are usually bulky back-packs, so the divers developed a body-hugging version, essential for tight passages.
The boys, aged 11 to 16, and their 25-year-old coach disappeared when flooding trapped them after entering the Tham Luang Nang Non cave
Mr Volanthen has said of cave-diving: ‘I enjoy the logistical challenge. Getting us and all our kit to the end of such a long cave… it’s like that puzzle with the fox, the chicken and the grain. It’s not dangerous if you do it right.’
Before the Thailand mission, Mr Stanton said his greatest achievement was helping rescue trapped British soldiers from a cave in Mexico in 2004.
After being awarded the MBE in 2012, Mr Stanton said: ‘Who would have thought taking up a hobby in cave diving would take me all over the world and lead to all these awards and now an MBE?’
In 2010 he and Mr Volanthen were hailed for their courage after they descended almost 1,000 metres through flooded passages in search of a French cave explorer trapped for more than a week beneath the gorges of the Ardeche in southern France.
Eric Establie, who was believed to have been trapped when a section of a cave collapsed, was eventually found drowned.
Both men were awarded a bronze medal from the Royal Humane Society in recognition of their attempt.
He and Mr Volanthen’s latest mission in Thailand, where they have been accompanied by a third Briton, Robert Harper, saw them navigate their way through flooded caverns to find the 12 boys and their coach nine days after they went missing.
Bill Whitehouse, vice-chairman of the British Cave Rescue Council, said: ‘I gather the actual diving section was about 1.5km, about half of which was completely flooded, and the total dive was about three hours.’
Mr Harper, from Somerset, began caving in 1968 and is said by Wessex Cave Club to have ‘extensive experience throughout Britain’, and in Switzerland and France.
Yesterday Mr Volanthen’s mother Jill told of her ‘absolute pride’ in her son. ‘I felt absolute relief for the children and for the mothers of the children,’ she told the BBC.
Mr Stanton’s former fire service colleague Watch Commander Alex Daw, of West Midlands Fire Investigation Prevention, said: ‘If it was me stuck anywhere, the one person I would want to come and rescue me is Rick Stanton.’