The Mayor of London has powers similar to a king, according to Boris Johnson.

In an interview with the LondonLovesBusiness website, Johnson said the top job in the capital comes with more direct power than the prime minister or a cabinet minister.

"I am convinced I have more power, executive authority, ability to change people’s lives directly and get things done fast and in a wonderful way than any secretary of state. Really and truly," he said.

"The constitution of this country is now very peculiar because, in my view, in the mayoralty in London you’ve created the most fantastic job that any politician could want to do."

Johnson, who is engaged in a battle to stop Labour's Ken Livingstone from taking back the crown, said that while David Cameron had "supreme executive authority" most of the practical decisions were made in Whitehall departments and not at the desk of the prime minister.

"But here the mayoralty is effectively a monarchy," he said.

The formal election campaign for London Mayor starts on Tuesday with the election due to be held on Thursday 3 May. As well as Livingstone, Johnson faces challenges from Lib Dem Brian Paddick and the Green party's Jenny Jones.