With almost four years still to go until the London Olympics, police have been put on alert for widespread fraud after receiving reports of scams ranging from websites offering fake tickets to “boiler rooms” selling shares in companies with fake games-linked contracts.

Steve Wilmott, City of London police’s head of economic crime, said the internet air ticket scam suffered by the parents of Rebecca Adlington, the British swimmer who won two gold medals, was a telling sign of frauds that could flourish around London 2012.