A series of betting slips left to Oxfam through a man’s legacy could land the charity over £300,000 in the next ten years.

Nicholas Newlife, 69, from Kidlington, Oxfordshire, placed £4, 420 worth of long-term wagers between 2000 and 2005 with bookmakers William Hill.

The slips were left to Oxfam, alongside his entire estate, when Newlife passed away in February 2010. A third of a million pounds is pinned on the future successes of tennis stars Roger Federer and Andy Roddick, and cricketer Ramnaresh Sarwan.

Newlife currently has six outstanding bets, each with the potential to gain thousands of pounds.

A £1,520 bet on Federer to win Wimbledon’s men’s singles at least seven times before 2020 could generate £101,840 for Oxfam, while a £750 wager on Andy Roddick to win at least 10 grand slam singles titles before 2020 could see the civil society organisation gain £75,075.

“We’re enormously grateful to Mr Newlife for his generous gift, and will be keeping a close eye on Wimbledon this year as a result,” said Cathy Ferrier, fundraising and supporter marketing director at Oxfam.

Graham Sharpe, media relations director at William Hill, said, “Roger Federer is already 6/4 hot favourite to win this summer's Wimbledon and I fully expect to be handing over a six figure [£101, 840] cheque to Oxfam when he does so.”

“To ensure that a respected charity would benefit from any bets which came to fruition after his death makes him unprecedented in my 30-year experience of the betting industry,”.he said.

Oxfam currently receives 600 legacies each year, which amount to 10 per cent of Oxfam’s total income from individuals. Other unusual legacy oddities include a letter written by Florence Nightingale and a pair of gold teeth accompanied by a dentist’s chair from a former dentist.