Labour will take “appropriate decisions” with regards to the party leadership if the election results are as bad as the exit poll suggest, Jeremy Corbyn’s chief lieutenant has suggested.

In the minutes following the news that the Conservatives look on course for a large majority, John McDonnell told the BBC that the results would be “extremely disappointing”.

Asked whether Mr Corbyn would resign, Mr McDonnell said: “We’ll see the results in the morning and then decisions will be made, I’m sure then. Let’s see the results. We’ll make the appropriate decisions. We’ll always make the decisions in the best interests of our party.”

Meanwhile Jon Lansman, the founder of left-wing group Momentum, commented "Jeremy will have to make those decisions himself. Jeremy has always been a reluctant leader." He added that the decision did not need to be taken “until the New Year”.

Mr Corbyn is likely to come under pressure to quit in the coming days if the results of the exit poll are borne out. As the votes were counted, one Labour's, Siobhain McDonagh, said the result was "one mans fault" – that of the Labour leader.

General election 2019: Dogs, Santa and even Elmo at the polls Show all 35 1 /35 General election 2019: Dogs, Santa and even Elmo at the polls General election 2019: Dogs, Santa and even Elmo at the polls Somerset A man dressed as Father Christmas enters his grotto at the Dunster Tithe Barn AP General election 2019: Dogs, Santa and even Elmo at the polls A dog dressed as a bee at a polling station DaveMcgrath1/PA General election 2019: Dogs, Santa and even Elmo at the polls Edenbridge Voters arrive on horses at The Rock Inn pub, being used as a polling station in Chiddingstone Hoath AFP via Getty General election 2019: Dogs, Santa and even Elmo at the polls Stocksbridge A woman waits outside a cafe, set up as a polling station AFP via Getty General election 2019: Dogs, Santa and even Elmo at the polls London People queue to cast their ballots, at polling station in Clapham Kelly Molloy/AP General election 2019: Dogs, Santa and even Elmo at the polls London Labour leader Jeremy Corbyn and his wife Laura Alvarez pose outside the polling station at Pakeman Primary School in Holloway Getty General election 2019: Dogs, Santa and even Elmo at the polls Hartlepool A dog stands next to a polling station sign Getty General election 2019: Dogs, Santa and even Elmo at the polls Glasgow Leader of the Scottish National Party Nicola Sturgeon waves as she leaves a polling station after voting Reuters General election 2019: Dogs, Santa and even Elmo at the polls London Boris Johnson holds his dog Dilyn as he leaves a polling station, at the Methodist Central Hall Reuters General election 2019: Dogs, Santa and even Elmo at the polls Millie wearing a Christmas outfit at a polling station Sewingloon/ Lewis MacDonald via AP General election 2019: Dogs, Santa and even Elmo at the polls A person dressed as Sesame Street character Elmo next to police officers after arguing with a member of Jeremy Corbyn's security detail Reuters General election 2019: Dogs, Santa and even Elmo at the polls Yorkshire A dog next to a polling station sign on the back of a Land Rover in Low Row PA General election 2019: Dogs, Santa and even Elmo at the polls Northern Ireland DUP leader Arlene Foster arrives at a polling station in Enniskillen PA General election 2019: Dogs, Santa and even Elmo at the polls London Nuns leave after voting at St John's parish hall AFP via Getty General election 2019: Dogs, Santa and even Elmo at the polls Arundel Signs are photographed at a polling station at the Arundel Lido swimming pool facilities Reuters General election 2019: Dogs, Santa and even Elmo at the polls Eight dogs at a polling station in Dulwich Village PA General election 2019: Dogs, Santa and even Elmo at the polls Oxford A presiding officer and a clerk drink cups of tea next to heaters to keep warm as they sit inside their polling station at Ace Laundrette AP General election 2019: Dogs, Santa and even Elmo at the polls Hove A dog sits outside a polling station Grizelda Cartoons via Reuters General election 2019: Dogs, Santa and even Elmo at the polls Brighton Caroline Lucas leaves a polling station with her son Isaac Reuters General election 2019: Dogs, Santa and even Elmo at the polls Oxford A polling station set up inside a pub Getty Images General election 2019: Dogs, Santa and even Elmo at the polls Oxford A dog looks out of the door of a laundrette AFP via Getty Images General election 2019: Dogs, Santa and even Elmo at the polls New Mills A polling station sign is displayed next to a nativity scene as a voter arrives at a polling station at the Town Hall Getty General election 2019: Dogs, Santa and even Elmo at the polls Glasgow Liberal Democrats leader Jo Swinson and her husband Duncan Hames leave a polling station after voting Reuters General election 2019: Dogs, Santa and even Elmo at the polls A horse outside a polling station in Epping Forest FSCEPPINGFOREST via Reuters General election 2019: Dogs, Santa and even Elmo at the polls Narberth A woman leaves a polling station at Hank Marvin, a fish and chips restaurant Reuters General election 2019: Dogs, Santa and even Elmo at the polls Mayor of London, Saqid Khan poses with a dog Luna outside a polling station in an undisclosed location in this still image taken from a video uploaded to social media on December 12, 2019 . Saqid Khan/via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. MANDATORY CREDIT. NO RESALES. NO ARCHIVES. SADIQ KHAN Sadiq Khan via REUTERS General election 2019: Dogs, Santa and even Elmo at the polls A man leaves a polling station in a railway carriage in Leeming Bar, North Yorkshire, as voters go to the polls in what has been billed as the most important General Election in a generation. PA Photo. Picture date: Thursday December 12, 2019. See PA story POLITICS Election. Photo credit should read: Danny Lawson/PA Wire Danny Lawson PA General election 2019: Dogs, Santa and even Elmo at the polls A woman clears the snow at the entrance of a polling station during the general election, in Dalwhinnie, Britain, December 12, 2019. REUTERS/Russell Cheyne RUSSELL CHEYNE REUTERS General election 2019: Dogs, Santa and even Elmo at the polls A man walks outside of a polling station next to the Thelnetham Windmill on the day of the general election in Suffolk, Britain, December 12, 2019. REUTERS/John Sibley JOHN SIBLEY REUTERS General election 2019: Dogs, Santa and even Elmo at the polls Horses are tethered outside The Rock Inn pub, being used as a polling station in Chiddinstone Hoath, near Edenbridge, south-east England on December 12, 2019, as Britain holds a general election. (Photo by Ben STANSALL / AFP) (Photo by BEN STANSALL/AFP via Getty Images) BEN STANSALL AFP via Getty Images General election 2019: Dogs, Santa and even Elmo at the polls Handout photo taken with permission from the Twitter feed of @onzlo99 of a queue outside a polling station in Balham, London as voters line up to cast their votes in the General Election. PA Photo. Issue date: Thursday December 12, 2019. See PA story POLITICS Election. Photo credit should read: @onzlo99/PA Wire NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder. @onzlo99 PA General election 2019: Dogs, Santa and even Elmo at the polls HIGH PEAK, ENGLAND - DECEMBER 12: Two dogs sit outside a Polling station at St Matthew's Church in Hayfield on December 12, 2019 in High Peak, England. The current Conservative Prime Minister Boris Johnson called the first UK winter election for nearly a century in an attempt to gain a working majority to break the parliamentary deadlock over Brexit. The election results from across the country are being counted overnight and an overall result is expected in the early hours of Friday morning. (Photo by Anthony Devlin/Getty Images) Anthony Devlin Getty Images General election 2019: Dogs, Santa and even Elmo at the polls An election worker adjusts a sign on a polling station in a container outside The Olympian Boxing Club during the general election in Sunderland, Britain, December 12, 2019. 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Mr McDonnell blamed the apparent poor result on the campaign’s focus on Brexit dividing the party's coalition of voters.

“I hate to use the expression, I think people probably did want to ‘get it done’,” he admitted, calling back to the Tory campaign slogan.

But he issued a warning to voters: “Let me be clear: I’m not sure Brexit will be done as a result of this. I think what will happen is that people almost in despair wanted to get Brexit over and done with because they’ve had enough of what’s going on ... I think people on all sides were just frustrated and wanted Brexit out of the way. But the disappointment that they’ll find is that Brexit isn’t going to go away. What will happen is that there’ll be negotiations for a long time.”

Labour's Gareth Snell, who is expected to lose his Stoke seat added: "It would be remiss of me not to mention that Jeremy Corbyn has come up on the doorsteps. Some people really like him. Some people really dislike him, and that has been a turnoff.

"But John [McDonnell] is right to say that it’s Brexit. The Labour party had a choice when Theresa May presented her deal. We could either have stopped the Tories or we could have stopped Brexit. And unfortunately some of the siren voices in the shadow cabinet who have big Liberal Democrat votes in their London seats decided that stopping Brexit, and therefore lining themselves up for future leadership bids, was much more important than respecting the votes in marginal constituencies in the midlands and in the north west and the north east. And they’ve sacrificed us for whatever political ambitions they want to do next."

Others disagreed. In a tweet, Exeter MP Ben Bradshaw said that his local party had gathered data and that "among every voting group the overwhelming negative for us was the leadership, not Brexit".

On the overall scale of the apparent defeat, Mr McDonnell said: “If it is anywhere near this this will be extremely disappointing for the party overall and for our movement, yes it will. I thought it would be closer, I think most people thought the polls were narrowing. We knew it would be tough because Brexit has dominated this election,” he said.

“I think Brexit has dominated everything by the looks of it. We thought other issues could cut through and there could be a wider debate. From this evidence they clearly didn’t.”

Defending Mr Corbyn’s leadership, he added: “There were issues raised because of the media campaign against him [Corbyn] of course there were, but as we moved through the campaign we saw that actually his polling ratings began to rise quite well.”