It takes to £750 million ($1.1 million) the total raised for London 2012 through sales of such games, including Dream Number, certain scratchcards and all interactive instant win games, so far as part of a wider Lottery contribution of £2.2 billion ($3.3 billion).

The money raised is helping fund the building of the facilities for 2012, including the Olympic Stadium, Aquatics Centre and the Velodrome.

Dianne Thompson, the chief executive of Camelot, operator of the National Lottery, said: "We are delighted that the £500 million milestone has already been reached, with over two years to go until London 2012.

"We'd like to thank National Lottery players for this fantastic achievement - by playing specially designated games, they are playing a crucial part in making the London 2012 Games the greatest sporting event the nation has ever seen and creating a lasting legacy for the whole of the UK."

Sebastian Coe, the London 2012 chairman, said: " The £500 million raised by National Lottery players is great news and I'd like to thank everyone for their support of the London 2012 Games."

To help celebrat the achievement five-time Olympic gold medallist Sir Steve Redgrave today helped launched a new nationwide quiz, The Games Brain of Britain, to find Britain's most knowledgable expert on the Olympics and Paralympics.

Sir Steve said: "Raising £500 million for London 2012 from designated games with over two years to go is a phenomenal achievement by Lottery players.

"It's great to see the UK getting behind the approaching Games and what a fantastic way to begin the countdown by opening up the challenge to find the UK's expert in Olympic and Paralympic knowledge.

"I hope people the length and breadth of the UK will take up the challenge - it will be fascinating to find out just what a nation of aficionados of the Olympics we are in the run-up to the Games."

Coe, who as the only runner to win two consecutive Olympic 1500 metres titles as well as two silver medals in the 800m, is sure to feature as a question in The Games Brain of Britain.

He said: "The Games Brain of Britain is a fantastic challenge and is a great way to enthuse the public about the Olympic Games and Paralympic Games.

"I'm looking forward to seeing who emerges as the UK's expert."

For more information on The Games Brain of Britain click here.

Contact the writer of this story at [email protected]