Liberal Democrat leader Sir Vince Cable fluffed the key line in his closing speech to his party’s conference.

Journalists had been briefed Sir Vince would speak of Leave campaigners experiencing an “erotic spasm” over a hard Brexit.

Instead, the veteran MP grimaced as he stumbled over the phrase, saying “exotic spresm” instead.

The mistake overshadowed the rest of his speech, where Sir Vince tried to reach out to Leave voters, saying that he understands their anxieties and that wanting to manage immigration is not racist.

The former business secretary said people had genuine fears that globalisation was turning secure jobs into “crap” ones.

Demanding a fresh EU referendum, the Lib Dem leader rounded on hardline Tory Brexiteers and was supposed to say they got an “erotic spasm” from the thought of breaking with Brussels, whatever the cost to the economy.

But he said instead: “To the ‘true believers’ – the fundamentalists – the costs of Brexit have always been irrelevant.

“Years of economic pain justified by the exotic spresm of leaving the European Union. Economic pain felt – of course, not by them – by those least able to afford it.”

The ex-business secretary said: “I don’t accept the idea that it is some form of racism to want immigration to be managed like other parts of the economy.

“To dismiss all Brexit voters as racists is simply wrong and utterly counter-productive.”

Sir Vince said parts of the country felt “left behind” and the Lib Dems had to combat the false perception that overall immigration had damaged wages.

“Deindustrialisation, globalisation … all these ‘tions’ that were supposed to represent progress have often meant a move from skilled and respected jobs to crap jobs – from certainty to insecurity.”

Vince CableLiberal Democrats Leader Sir Vince Cable, accompanied by his wife Rachel arrives at the conference centre (Gareth Fuller/PA)

The Lib Dem leader said the EU may be moving to reform free movement of labour and Britain should remain in the bloc to help shape that.

Sir Vince called for Labour to topple Mr Corbyn if he did not back a new referendum.

“If Jeremy Corbyn will not say ‘I will support a people’s vote and I will fight Brexit’, Labour members should wave him goodbye.”

And Sir Vince said: “He has kept his hands clean and his image polished by hiring hard-left boot boys and girls to do his dirty work.

“They do the bullying and intimidation of colleagues and he claims not to know.

“He indulges anti-Semitic bigots and pleads ignorance.”

Sir Vince also said Prime Minister Theresa May does not believe in Brexit.

He said: “She is dutifully delivering a policy she doesn’t really believe in – failing in negotiations, losing public support – and all to appease a dwindling group of angry people in her party who will denounce her as a traitor, whatever she comes up with.”

He also launched a personal attack on Boris Johnson, comparing him to US president Donald Trump, saying: “Their cynical disregard for the truth, their treatment of women, and their inflammatory divisive language make Boris and Donald the terrible twins of the rabid right.”

The Lib Dem leader called for an increase in wealth taxes as he branded Amazon, Facebook and Google “world-class tax dodgers”.

Saying that the “tectonic plates of British politics are shifting beneath us” as Labour and the Tories become more hardline, he urged disillusioned MPs to jump ship.

“Much now depends on the courage of mainstream MPs in the Labour and Conservative parties. They are losing control and if they can’t stop the rot, they should leave.”

Drawing on his own experiences of racism, Sir Vince said: “I embarked on a mixed marriage in this country when racism was rife. My wife and children were being denounced as people whose very presence here would lead to rivers foaming with blood.

“And I was thrown out of the parental home.”

Sir Vince, who has announced he wants to hand over the reins of his party to the next generation, insisted the Lib Dems need a major shake-up.

“Our party is still very pale and very male.”