The two British divers who found 12 missing boys and their football coach alive in a flooded cave in Thailand boast extensive experience. Rick Stanton and John Volanthen, who reached the group nine days after they vanished, are so well known among cave rescuers that they had reportedly been requested specially. Yet their work is entirely voluntary; one is a firefighter, the other a computer engineer. And far from glorying in their role, Mr Volanthen had brushed off reporters as he entered the cave, saying only: “We’ve got a job to do.”

On first sight, their quiet courage and extraordinary expertise are truly exceptional. Yet what is perhaps more remarkable is that thousands of people in the UK volunteer on search and rescue teams, and do so largely unsung. There are around 1,000 volunteer cave rescuers in the UK, and 4,700 volunteer lifeboat crew members. In 2015, more than 1,720 people helped in mountain rescue operations. Lowland and coastguard cliff rescue teams are even less well known. But together their impact is powerful. The Royal National Lifeboat Institution says its volunteers have saved more than 139,000 lives since its foundation in 1824. Local people have always helped out – or been drafted in – when someone has got into trouble. But such ad hoc efforts often lacked appropriate skills, experience, coordination and equipment. And as rescuers themselves point out, the very fact of volunteering gives them a different impetus.

There is often a strong element of self-preservation, at least in the genesis of such groups; the British Cave Rescue Council says volunteers are usually rescuing fellow cavers who have got into difficulties. There are other, not purely altruistic, spurs: the satisfaction of overcoming tough challenges; the adrenaline of racing against the clock; the camaraderie of working as a team; the thrill of saving a life – and, for some, the ego-boost of saying they have done so. But rescuers sacrifice their free time, work in gruelling conditions and face the trauma of failed attempts. And while part of the immense dedication required is to developing, rehearsing and implementing systems to reduce the risks, they will still put themselves in real peril for the sake of another at times.

Dr Ian Greatbatch, editor of the Journal of Search and Rescue and formerly a lifeboat volunteer for more than a decade, describes how a search-and-rescue dog team offered members of the public the chance to bring their pets for training. In the end they dropped the initiative, after finding almost any dog could do it. In his words, “there is no dark art: search-and-rescue volunteers are not superheroes, but people who have decided to do it”. That is not to belittle their contribution; rather, it is what makes it truly outstanding. Perhaps more of us could launch ourselves into churning seas, ascend steep crags in bitter winds or battle the currents through tiny, cramped cave passages, as Mr Stanton and Mr Volanthen have done. But very few will do so.