One of them was known as the “Prince of Darkness” and the other is seen as the dark lord of Jeremy Corbyn’s Labour Party.

But Labour sources say Lord Mandelson and Seumas Milne have rekindled an “odd couple” friendship which goes back to the 1980s.

The two political strategists who share a penchant for spin and an uncompromising approach to their opponents — if not their politics — have been spied at social gatherings and in the House of Commons in recent months.

Lord Mandelson said he respects Milne’s work ethic

A well-connected Labour source claimed they had also spoken on the phone, sparking speculation that the sometime Soviet sympathiser behind Corbyn’s revolution has been picking the political brains of the man who helped Tony Blair to win three general elections.

A memo