Harry Potter author JK Rowling has led criticism of Jeremy Corbyn after the Labour leader re-committed his party to going ahead with Brexit if he became prime minister.
In a newspaper interview, Mr Corbyn stressed that even if Labour won a snap general election in 2019 he would seek to "go back and negotiate" a Brexit deal with the EU in time for the UK to still leave the bloc on 29 March next year.
He also failed to commit Labour to backing Remain if there were a second EU referendum.
Mr Corbyn's refusal to budge from his party's manifesto commitment to respect the result of the 2016 Brexit vote has prompted anger from among both his party's MPs and high-profile supporters.
Rowling mocked Mr Corbyn's position – and his supporters – in a biblical-style series of Twitter posts she titled "The Visitation of The Corbynites".
She wrote: "And she did answer, 'How shall the poor fare under Brexit, which thy Saint hath always in his secret heart desired, yet he hath not admitted what was in his heart, lest fewer attend his next Sermon on the Glastonbury B Stage.'
"And they did answer, 'Saint Jeremy will achieve a miracle, and he shall bring forth a Jobs First Brexit and all the land shall rejoice.' And she did answer, 'b*******.'
"But she bethought her of the season of goodwill, and repenting of her ire she did speak further. 'I have, for all my life, voted Labour, yet now I cannot.'"
Rowling is a long-time Labour supporter but has frequently been critical of Mr Corbyn's leadership of the party.
Ahead of last year's general election, she posted a link to an article titled: "What should you do if you support Labour but can't stand Jeremy Corbyn?"
Rowling also referenced Labour's long-running antisemitism row in her messages, which were branded "bloody brilliant" by former England footballer Gary Lineker.
In his interview with the Guardian, Mr Corbyn said: "It would be a matter for the party to decide what the policy would be; but my proposal at this moment is that we go forward, trying to get a customs union with the EU, in which we would be able to be proper trading partners."
In addition, the Labour leader denounced current EU state aid rules as preventing a possible Labour government from being able to help "develop industry" in the UK.
The comments were denounced by Labour MPs who want Mr Corbyn to throw his support behind a second EU referendum.
Ilford North MP Wes Streeting tweeted: "Why peddle this myth that Labour would be able to renegotiate a Brexit deal at this 11th hour?
"How would Labour's Brexit be any better than remaining in the EU? Our members and voters are overwhelmingly pro-European. This lets them, and our country, down."
Liverpool Wavertree MP Luciana Berger wrote: "@UKLabour will never be forgiven if the party facilitates Brexit. It's been made patently clear that there isn't a 'better' Brexit.
"Electorally we wld slump to 3rd place on 22% (behind LD's 26%). We need a #PeoplesVote -the wish of 77% Labour supporters."
And Ilford South MP Mike Gapes posted: "How many times do we have to say it ? There is no better Brexit. There is no jobs first Brexit. There is no Socialist Brexit. But Corbyn does not want to stop Brexit. He supports Brexit."
Mr Corbyn is opposed to Theresa May's Brexit deal and vowed to push for a general election if the prime minister's agreement is rejected by MPs.
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He has also not ruled out the option of supporting a second EU referendum, should Labour be unable to force an election.
But, Mr Corbyn is coming under increasing pressure to make that switch now.