The world’s top business leaders are using their visit to the London Olympics to raise tough questions about the coalition’s management of Britain’s stagnant economy and the country’s vulnerability to a euro break-up.

While David Cameron, prime minister, is trying to use the games as a showcase to boost UK trade and investment, chief executives from the US and Asia – many of them big investors in Britain – are privately voicing anxiety at the state of the economy.

“Cameron is giving us a big sales pitch, but we are not taking any notice of that,” said the head of an Asian multinational. “We want to know what’s happening to the economy and what are the prospects for us.”