BOOKMAKER William Hill is still waiting to see a birth certificate that proves fund-raising London Marathon runner Buster Martin really was 101 years old when he completed the race in April.

In fact, Buster is now claiming to be 102 - following birthday celebrations in London on Monday.

The Epping-based Rhys Daniels Trust will receive over £13,000 if two bets relating to the race are honoured.

William Hill says it has offered to pay a nominated charity £6,500 if Buster's age can be proved beyond doubt, by production of his birth certificate.

The bookmakers said it laid a bet of £101 at odds of 101-1 about Buster - who it had been led to believe was 101 years old - completing this year's London Marathon in under 12 hours, on condition that Buster or his employer could prove his date of birth, claimed to be September 1, 1906.

William Hill spokesman Graham Sharpe said: “It’s a remarkable achievement to complete the London Marathon whether you’re 21, 61, 91 or 101, but the whole basis on which the odds were calculated was that we were assured Buster would become the first 101-year-old, the first centenarian and the oldest competitor yet to complete the London Marathon.

“However we were concerned to learn that neither the race organisers nor the Guinness World of Records were prepared to accept Buster's age as the necessary proof had not been forthcoming.”

A second bet (£100 at 33-1) was laid that Buster would complete the course by midnight.

William Hill has said that “as a gesture of goodwill” it will pay the Rhys Daniels Trust £13,501 (winnings excluding stake money, which was donated by Hills) - the total amount which Mr Martin would have collected if the terms of the bets had been met.

Mr Sharpe said: “It seems unfair to us that a charity, albeit one with no direct connection to the staking of these bets, should be left with the impression that it is somehow worse off as a result of the inability of Mr Martin and his employers to prove his age.

“Therefore, purely as a gesture of goodwill, we will make a payment equivalent to that which they may have received from Mr Martin, had he been able to authenticate his date of birth.

“It is inexplicable to us that a company (Pimlico Plumbers for whom Buster works three days a week, cleaning its vans) which has chosen to utilise an employee as a walking - sometimes running – 101-year-old public relations exercise, should not have obtained the relevant proof of age in advance of so doing, thus exposing an elderly gentleman to the embarrassing situation which has arisen as a result.

“If and when Mr Martin's birth certificate is finally produced for inspection, and the French Embassy has assured us that it should be a straightforward matter to obtain it, we will be delighted to make up our donation to the Rhys Daniels Trust to a total of £20,000.

“It would be appropriate if the proof were to be forthcoming, as it would permit Mr Martin to celebrate his birthday in a few days' time in the certain knowledge of how old he actually is!”

Karl Plunkett, spokesman for Pimlico Plumbers, said: “It’s very good of them (William Hill) to have told the charity that they will get the money.

“We are still actively pursuing parish records in rural France looking or the birth certificate and hopefully when we track it down William Hill will come up with another £6,000 for the Rhys Daniels Trust which they can dearly do with.”

• Celebrities Christopher Biggins and Bobby Davro were among the 200 people who attended Buster’s birthday party.

Buster, part of The Zimmers pop group, performed, while Bobby Davro took to the microphone to entertain the partygoers.

Pimlico Plumbers spokesman Karl Plunkett said: “The day was absolutely, completely and utterly mad. There were loads of people. Buster had a great time, he enjoyed himself and had plenty of ale – his specially brewed Buster’s Best Bitter.”