LONDON (REUTERS) - The economic benefits of hosting the Olympics in London already outweigh the £9 billion (S$17.2 billion) of public money spent on the Games, the British government said on Friday.

A year on, the Games remain a fond memory for most Britons, who recall the triumphs of runner Mo Farah and cyclist Chris Hoy but have gone back to their daily routines in a country where the economy is showing signs of life after a long stagnation.

Keen to show that the London 2012 Games had a lasting impact, the government said it calculated Britain had enjoyed a £9.9 billion boost to trade and investment from staging the world's biggest sporting event. Spending by foreign tourists also rose by £600 million in 2012.

But while the figures show that Britain is well on the way to surpassing a target of £13 billion in economic impact set by Prime Minister David Cameron ahead of the Games, economists had previously questioned the basis for government predictions.

They caution that it is difficult to quantify the exact economic impact of major sporting events like the Olympics and that the sums involved tend to be relatively modest.

Britain tried to use the international attention focused on the Olympics to showcase itself as a place to do business. The government ran a series of conferences in parallel with the Games to drive home its message to hundreds of executives who came to the British capital.

"We are harnessing the Olympic momentum and delivering the lasting business legacy of the Games that will help make Britain a winner in the global race," Prime Minister David Cameron said in a statement.

A separate report by a consortium led by accountants Grant Thornton said the Games could generate benefits of between £28 billion and £41 billion by 2020.

UK Trade and Investment, the department which produced the government figures, said it included £5.9 billion of sales from conferences around the Games, £2.5 billion of additional inward investment and £1.5 billion of contracts for forthcoming Olympics and World Cups with Brazil and Russia.

It included an investment in London's landmark Battersea power station by a Malaysian consortium without specifying how it was directly related to the Games. Also listed were projects involving Chinese technology company Huawei, Indian software firm Infosys and US architects Gensler, giving no details of the nature of the investment.

Figures aside, Britain looks to be well on the way to finding new uses for the expensive facilities built for the Games in East London, although there has been some grumbling over the deals struck.

Premier League football club West Ham United are to move into the Olympic Stadium in 2016, ensuring that it remains a part of the city's sporting landscape but securing only an initial £15 million for a stadium that cost taxpayers more than £500 million.

The stadium has not been used since the Paralympics ended last September but will come back to life next week when it hosts the Anniversary Games athletics meet which is expected to feature Jamaican sprint champion Usain Bolt.

The most tangible result of the Games for now is the changes wrought to a once-forgotten and polluted corner of the city's industrial east. Stratford, home to the Olympics and one of the poorest parts of the capital, now boasts Europe's largest urban shopping centre and excellent transport links to the rest of the capital.