Boris Johnson cannot deliver his manifesto promise to secure a new Brexit trade deal by the end of 2020, the EU’s chief negotiator has said.

In a leaked recording of a private talk with MEPs, Michel Barnier said the Prime Minister’s 11-month timetable was simply “unrealistic”.

The SNP said it had exposed Mr Johnson’s “big Brexit con”

The Tory manifesto promise to “get Brexit done” involves getting Mr Johnson’s Brexit deal through parliament to allow the UK’s formal exit from the EU on January 31.

The UK would then enter an implementation phase, when EU rules still apply, to allow the country and the EU 27 nations to negotiate a long-term free trade deal on new terms.

The manifesto states: “We will negotiate a trade agreement next year ...and we will not extend the implementation period beyond December 2020.”

Most experts think this is impossible, given trade deals typically take several years, and so there could be a no-deal Brexit if Mr Johnson refused to negotiate beyond 2020.

In the recording, Mr Barnier said: “With regards to this agreement, we will not get everything done in 11 months.

“We will do all we can - we won’t do it all.

He continued: “It is unrealistic that a global negotiation can be done in 11 months, so we can’t do it all.

“We will do all we can to get what I call the ‘vital minimum’ to establish a relationship with the UK if that is the time scale.

“If there is no extension, we will still have a few months to achieve what I would describe as the minimum necessary for the economy and security or to prepare for a cliff-edge.

“Either we have a trade agreement or we will be in the WTO framework.

“We can’t take contingency measures on trade to give us more time … If there’s no deal, it is a cliff edge for trade.”

Stephen Gethins, the SNP’s Europe spokesperson and candidate for Fife North East, said: “Boris Johnson’s big Brexit con has once again been exposed for the blatant lie that it is, after the EU’s chief negotiator revealed that the Tories’ timetable is simply ‘unrealistic’ and trade talks will not be finished by 2021.”

Labour’s Andrew Gwynne said it showed the Prime Minister was “playing the British public for fools”.

He said: “He’s hiding in fridges to dodge interviews precisely because his fake Brexit slogans can’t stand up to scrutiny, just like his empty words on the NHS.

“Johnson’s sell-out Brexit deal will put us on the fast-track to a cliff-edge no deal Brexit.”

LibDem Tom Brake added: “Michel Barnier’s comments are further proof that Boris Johnson’s key campaign slogan is just another Tory fib.”

A Tory spokesman said: “Barnier also said the Withdrawal Agreement couldn’t be reopened and the backstop would never be removed. The PM secured a new deal that abolished the backstop.”