Brexit trade negotiations cannot be finished in the timeframe claimed by Boris Johnson, the EU’s chief negotiator has privately admitted – blowing a hole in the prime minister’s big election promise to “get Brexit done”.

In a leaked recording obtained by The Independent, Michel Barnier tells a private meeting that the UK’s 11-month timetable to wrap up trade talks by 2021 is “unrealistic” and suggests negotiations will drag on until long after the end of next year.

“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,” Mr Barnier can be heard telling a group of senior MEPs at the closed meeting in the EU capital this week.

The recording sparked consternation from Mr Johnson’s critics back in the UK, with the prime minister accused of “lying to voters” about Brexit and “playing the British public for fools”.

Mr Barnier, who was recently reappointed to lead the next round of Brexit talks for the EU side, told the meeting: “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.”

He added that without a further extension of EU rules and regulations to Britain of one or two years there would be another “cliff edge” that could see Britain crash out on World Trade Organisation rules.

“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,” the chief negotiator said – adding that the decision would have to be taken by the government in June, just over six months from now.

“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.”

The revelations will trouble voters thinking of supporting Mr Johnson’s Conservatives on Thursday on the basis that the party would “get Brexit done” and put the divisive issue in the country’s rear-view mirror.

Far from ending the saga, the tape shows that EU officials are planning for contentious talks to stretch on for years in much the same vein as they have since 2016.

Mr Barnier has publicly entertained Mr Johnson’s claims about timescales, in the apparent belief that the prime minister is the best hope for getting the withdrawal agreement through parliament. But in Brussels and other capitals the fact a free trade agreement cannot be negotiated in 11 months is an open secret among officials – as illustrated by the new tape.

We will not get everything done in 11 months. We will do all we can – we won’t do it all Michel Barnier, EU chief negotiator

On Wednesday, giving his final address to voters, Mr Johnson said he would “deliver on the result of three years ago and then move on, focus on the people’s priorities”.

He claimed that arguments about Brexit would end by February – when the new round of talks would just be starting – and that the government would be able to “focus on the issues that matter to you”.

A spokesperson for the Conservative Party declined to comment on the revelations in the recording, but opposition parties reacted with fury.

“This confirms what we knew already, Boris Johnson is lying to voters about his damaging Brexit plans,” Liberal Democrat candidate Tom Brake told The Independent.

Boris Johnson has repeatedly said he would get Brexit done quickly (AFP)

“He is taking the British people for a ride and simply cannot be trusted to be our prime minister.”

Labour’s campaign chief Andrew Gwynne meanwhile said: “Boris Johnson is playing the British public for fools. 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 sellout Brexit deal will put us on the fast track to a cliff-edge no-deal Brexit. And that’s exactly what he wants, so he can drive the UK into a toxic trade deal with Trump and put the NHS up for sale to US drug companies.

Top 10 marginal seats to watch at the general election Show all 10 1 /10 Top 10 marginal seats to watch at the general election Top 10 marginal seats to watch at the general election North East Fife Currently held by the SNP with a majority of 2 Getty Top 10 marginal seats to watch at the general election Kensington Currently held by Labour with a majority of 20 Getty Top 10 marginal seats to watch at the general election Perth and North Perthshire Currently held by the SNP with a majority of 21 Getty Top 10 marginal seats to watch at the general election Dudley North Currently held by independent, formerly Labour, MP Ian Austin with a majority of 22 LivingInMediocrity Top 10 marginal seats to watch at the general election Newcastle-under-Lyme Currently held by Labour with a majority of 30 Derek Harper Top 10 marginal seats to watch at the general election Southampton Itchen Currently held by the Conservatives with a majority of 31 Rob Candish Top 10 marginal seats to watch at the general election Richmond Park Currently held by the Conservatives with a majority of 45 Robin Webster Top 10 marginal seats to watch at the general election Crewe and Nantwich Currently held by Labour with a majority of 48 Jaggery Top 10 marginal seats to watch at the general election Glasgow South West Currently held by the SNP with a majority of 60 Alec MacKinnon Top 10 marginal seats to watch at the general election Glasgow East Currently held by the SNP with a majority of 75 Christine Johnstone

“The only place Johnson’s sellout Brexit deal should go is into the deep freeze, just like Johnson when he doesn’t have the guts to face a reporter.”

EU leaders will meet in Brussels on Thursday and Friday this week for a summit without Mr Johnson, where they will discuss the next stage of Brexit talks and unveil their negotiating strategy and new instructions to Mr Barnier.

The strategy, which is due to be published just hours after polls close in the UK, shows talks will be much the same as before – led by Mr Barnier, with a string of make-or-break summits, and a new ticking clock and cliff edges, according to an early leaked draft revealed by The Independent last week. Leaders also conspicuously dropped a reference included in an earlier political declaration to use best endeavours to reach a deal by the end of the transition period.