A father and son will spend a month in Tokyo next summer – and their first drink there will be the sweetest of their life.

By then Mark and Sam Swain will have conquered saddle sores, extreme heat, rabid dogs and skirted Taliban territory during a year-long, 11,000-mile cycle ride.

They pedalled off from Dingle, on the west coast of Ireland, on a journey that will strip their relationship bare.

Mark, of Temple Road, Canterbury, said: “I have just turned 50 and Sam is 18 and this will be life-changing for both of us.

“We both know it will be incredibly hard at times but we have talked about this since Sam asked me how far Japan was when he was 10 years old.”

From Ireland they will ferry across to Swansea before passing back through Canterbury.

They will then set off for Dover and the Continent with best wishes from 200 of their friends at a farewell party in Temple Avenue.

Sam will leave behind post A-level jitters and Mark has handed over the reins of his consultancy business to a co-director for the first time.

Mark’s wife Lorna – a child psychologist – has given her blessing and the two are raising money for Canterbury-based charity the Rising Sun Domestic Violence Project.

Mark said: “My wife sees the results of just how damaging it can be when a father and son relationship breaks down.

“The most fascinating part of the trip for me is our relationship, as I think we will learn so much from one another.

“It has been really hard to leave the business to someone else but my clients have all been saying how jealous they are and not to worry.”

Christmas this year will be spent in India with wife Lorna and their daughter, Scarlett, 13, who will fly out to meet them.

Sam said: “I want to prove to dad that he won’t have to look after me everywhere and do everything for me. We’re both the kind to say ‘let’s go over the next hill before we stop.’”

Both will keep diaries in what will become a warts-and-all testament to their epic ride and Mark plans to turn those notes into a book.

Mark said: “I have spoken to Waterstone’s in Canterbury and they’re keen for us to do a talk on our return. Who knows where this trip will take us?”