There has been regular speculation about whether or not Boris Johnson has ambitions to take over the leadership of the Conservative Party from David Cameron.

Although overshadowed by his high-profile brother, Jo Johnson, a former journalist for the Financial Times who only entered Parliament in 2010, is regarded as a fast rising Conservative star.

Like Mr Cameron, he attended Eton College before Oxford University, where he was a member of the notorious Bullingdon club. He has previously been tipped as a future Prime Minister.

In his interview, Boris Johnson was asked whether he and his brother could have a similar political rivalry to Ed and David Miliband.

Since being defeated by his brother, David Miliband has regularly made his disappointment clear and has used articles and media appearances to snipe at the Labour leader.

He last month said that he would never be able to “erase” the memory of being beaten by his younger brother.

Asked whether he and his brother are “like” the Milibands, Boris Johnson said: “Absolutely not. We don’t do things that way, that’s a very left-wing thing … only a socialist could do that to his brother, only a socialist could regard familial ties as being so trivial as to shaft his own brother.

“I mean, unbelievable. Only lefties can think like that … they see people as discrete agents devoid of ties to society or to each other, and that’s how Stalin could murder 20 million people.”

Elsewhere in his interview Boris Johnson said that immigration has been “the lifeblood of London” but added: “But if you want to live in London, there are certain things you’ve got to sign up for – gender equality, freedom of speech, religious freedom.”

He also described immigrants attempting to enter Australia by boat as having “a lot of balls”.