Tom Power claimed that the German chancellor’s “obstinacy” placed Cameron in an impossible position – and was a major factor in Britain’s decision to withdraw from the bloc. During a candid interview with German magazine Spiegel, he also indicated that Johnson was not at “top level” and “lonely” – while insisting that he was far from finished as a political force, especially if he could achieve success in Brexit.

Referring to Brexit, Remainer Mr Bower, whose book “Boris Johnson: The Gambler” was published, said last month: “I’ll tell you something: My feeling is that the real villain in the entire Brexit drama is Angela Merkel.”

Cameron had triumphed in the 2015 general election on a pledge to renegotiate Britain’s membership in the European Union and hold a referendum afterward.

However, the package of measures he signed on 19 February 2016 was widely seen as containing a bit of substance that changed the UK’s position within the bloc.

However, in a likely allusion to Johnson’s struggle in the face of the pandemic – which he hospitalized after he himself contracted the virus – Mr. Bauer said that the prime minister “is not at his best,” adding: “He’s alone, makes him vulnerable.”

Referring to the infamous logo adorned on the Vote Leave campaign bus, Bauer admitted: “Admittedly, this was a lie.

However, it is not a lie designed to start a war.

“And in every election, opponents make false promises – you can believe it or not, 350 million pounds.”

Some observers have indicated that Mr Johnson has been in some form of discomfort since the Covid-19 bout which has led him recently to insist that he is “as fit as many butcher’s dogs”.

Bauer said Johnson still had a chance to regain the initiative in the coming months.

He explained: “If he gets the Brexit deal, and if the Corona crisis ends in the spring thanks to new vaccines, he will be revived again.”

“We have made it clear that we do not need an agreement at any cost,” Merkel said earlier this week, speaking in advance of the end of the transition period on December 31.

“We want one, but otherwise we will take the necessary measures – anyway, the agreement is in everyone’s interest.”

(Co-reporting by Monica Ballenberg)