Boris Johnson says David Cameron will be PM for a ‘very long time’

The Mayor’s comments, made during a radio interview in Australia, come after he predicted that his brother Jo Johnson, the head of Mr Cameron’s Downing Street policy unit, will one day be the Prime Minister.

Mr Johnson added: “If you look at what’s happening I Britain, the offering from the Labour Party is pitifully thin. It’s not at all clear what Ed Miliband and his guys stand for and I think David Cameron’s set there for a long spell."

The Mayor is in Australia for a family holiday as well as an appearance at a writers’ festival.

In his interview Mr Johnson also criticised the response of the Left to the banking crisis.

“The Left…nowhere around the world, not in America, not in Britain and not in Europe, nowhere did the Left produce a new critique of the market economy that was really valid after the banking crisis,” he said.

“They never really came up with a new model. They moaned about banks and they moaned about rich people but they never really came up with a new solution, a new way forward. All we had was the Occupy movement with a few flapping tents everywhere and that didn’t really add up to much.”