Carphone Warehouse founder Charles Dunstone has backed a letter warning voters of the dangers of a hung parliament.

The letter, being circulated among business leaders, is seen as a boost for the Conservatives, who have warned that Britain’s recovery is at risk if there is not an outright victory.

According to the Telegraph, opinion polls suggest that only the Conservatives have a realistic chance of forming a government without an alliance.

Dunstone, who is a friend of Tony Blair and known as a supporter of New Labour, is understood to have backed the letter along with former chairman of ITV Michael Grade. The businessmen warn that a hung parliament could “lead to weak and indecisive government that would put the recovery at risk”.

Although it does not openly back David Cameron, it says: “The next government faces a huge challenge to get the public finances back under control and to restore growth and prosperity. From our own experience in business we know that turning around a company requires clear vision and strong leadership. The same is true in government.”

It adds: “To secure jobs and investment Britain needs the certainty of strong leadership and government.”

Separately, eight business leaders have sent another letter today to the Telegraph warning that Tory plans to cut public spending this year “could risk tipping us into recession again with profound consequences”.