The London Olympic Games took place in July and August last year
The UK economy has seen a £9.9bn boost in trade and investment from hosting the 2012 London Olympic and Paralympic Games, research suggests.
A report for the government and Mayor of London attributes new contracts, additional sales and foreign investment in the last year to the Games.
Independent estimates cited suggest the total benefit to the UK will be between £28bn and £41bn by 2020, reports the BBC.
Last autumn the government put the projected cost of hosting at £8.9bn.
As well as the financial impact of the Games, the report - Inspired by 2012: The legacy from the London 2012 Olympic and Paralympic Games - highlights its influence on sport and regeneration.
It also says the Games volunteers inspired more people to take up similar roles in their communities.
The report adds 1.4 million more people than in 2005, when the Games bid was won, are playing sport at least once a week, and the legacy of all the permanent venues on the Olympic Park has been secured within a year of the Games.
Prime Minister David Cameron said companies across the country were "harnessing the Olympic momentum and delivering the lasting business legacy of the Games".
He added: "The Games are also delivering a strong social legacy. Last summer, Games Makers changed the way Britain views volunteering. Since then, thousands of people have been inspired to get involved with their local sports club."
And Business Secretary Vince Cable said: "A lot of people were very cynical about this... but as a result of all the work that was done we have this very considerable amount."
He said there was an "upward estimate" that, by 2020, the Games could have benefited the UK by as much as £40bn.
The report examined international trade and inward investment won "because of the Games and Games-time promotional activity".
The figures for economic growth are based on deals already signed as well as predictions of the expected value of future opportunities.
One engineering firm which was behind the Olympic park on the 2012 site said the Games had boosted its standing with other host countries and governments delivering large-scale transport and urban regeneration projects.
Describing the park as a "best in class example" of design and engineering, Mike McNicholas from the Atkins consultancy said: "What we saw in the run-up to the games was a huge interest from overseas governments and industry to look at how the Games was delivered."
The report also takes into account companies who stated their decision to invest in the UK had been influenced by the London Olympics, which took place in late July and early August, and the Paralympics in late August and early September.
Some £2.5bn of additional foreign investment into the UK since the Games is cited, such as the redevelopment of London's Battersea power station by a Malaysian consortium, and projects involving Chinese technology company Huawei and Indian software firm Infosys.
The report says British companies won £1.5bn of opportunities overseas, including work on other global sporting events such as the Brazil 2014 World Cup and Rio 2016 Olympic and Paralympic Games, and the Sochi 2014 Winter Games.
It also says there has been £5.9bn of additional export sales following Olympic-related promotions by the Foreign Office and UK Trade and Investment.
Lord Richard, a restaurant owner and chairman of the Restaurant Association, said the Games were "a terrific advert for London" that would bring more people to the city.