Tim wanted to thank Tenovus for helping his father

But west Wales dentist Tim Lewis set his sights even higher.

He gave himself a triple challenge for charity - which started with Sunday's world-famous 26-mile race.

As if that was not sufficiently gruelling, he has plans to cycle 200 miles back to Carmarthen afterwards, and then start preparing for a 5k fun run in his home town.

Mr Lewis, 45, is taking part in his 10th London Marathon - but he decided to make it a special occasion by giving himself a few extra goals.

After completing the course, he will get on his bike and ride back for a week' rest before joining his wife Angela in the annual mayor's fun run on Easter Monday.

Mr Lewis is hoping to raise up to �3,000 for Tenovus through his running and cycling.

He has supported Tenovus since the charity helped his father when he was treated for lung cancer.

He is hoping to complete the marathon circuit in about fourand-a-half hours.

Mr Lewis admitted his patients had questioned his sanity, with some saying they wanted to have treatment done before he went to London in case he did not make it back.

Depending on how he feels following the marathon, he will either allow himself a few hours' rest and leave London on Sunday, or leave first thing on Monday morning.

The marathon is the first of three challenges for Mr Lewis

He will follow the old route from London to Wales, going via the A40 towards Oxford, then through Stow on the Wold, over to Ross on Wye and through Brecon back to Carmarthen.

He is hoping to get home by Wednesday or Thursday, when he will have a well-earned rest over the Easter weekend before the Carmarthen Fun Run.

He will be accompanying his wife around the 5km circuit in her first road race.

Other Welsh runners in this year's marathon include :