Rugby legend Colin Charvis is training an intrepid team of military and police personnel as part of a £100,000 Help for Heroes fund-raiser.
A hardy 12-man team is in training for a rigorous 1,283-mile 10-day cycle marathon across the UK later this spring.
Not for the faint-hearted, the challenge will also see those taking part row across the Irish Sea and back and scale the UK’s four highest peaks.
They set out from John O’ Groats on May 22 and will mark their arrival at Land’s End by boarding a plane to skydive from 15,000 feet.
Charvis, a former Wales captain and British and Irish Lions veteran, is passing on fitness techniques used in his top-flight career.
He has joined members of the team at Headley Court, the world-leading rehabilitation centre of injured service personnel in Surrey, as preparations get under way.
The challenge, which unites armed services personnel from the Army, Royal Navy and Royal Air Force, is due to reach its finale in a mass skydive into Swansea on Friday, May 31.
By then the team hopes to have raised over £100,000 for the charity, which helps injured service personnel.
The quest has been made even more remarkable given that the team includes several amputees, injured while on active service in Afghanistan.
Charvis accepted a cheque for £10,000 yesterday from security firm G4S, which is sponsoring the initiative.
The company, which employs many former servicemen and women in roles from security guards to police support staff, has provided support equivalent to £20,000.
Charvis said: “I would like to thank G4S for the support they have provided for Heroes Challenge UK.
“Without this donation the team would not be able to attempt this incredible challenge, which will be a mammoth test of physical and mental toughness.”
He added: “The team will average more than 100 miles per day and their journey will be that little bit easier with the G4S guys in support.”