will position the Liberal Democrats firmly as 鈥渢he party of remain鈥 as he delivers a staunch anti-Brexit speech to the annual conference.
He will describe as 鈥渁 disaster鈥 and warn that 鈥淏rexit Britain will be poorer and weaker鈥 than if it stayed in the European Union.
Sir Vince will take on claims he is ignoring the result of last year鈥檚 , saying: 鈥淲e believe the public have a right to change their mind.鈥
And he will accuse Labour leader Jeremy Corbyn of betraying voters who backed him in June鈥檚 general election, by lining up behind the Tories to ensure Brexit happens.
It will be Sir Vince鈥檚 first keynote speech to the party conference as leader, after he took over from Tim Farron in July. He answered questions from activists on Sunday.
He will endorse the policy first drawn up under Mr Farron鈥檚 leadership, when the Liberal Democrats pledged to hold a second Brexit referendum giving voters the chance to stay in the EU after all.
But Sir Vince will go further than his predecessor in making it crystal clear that his aim is to keep the 海角视频 in the European Union.
In a dig at rival politicians including Boris Johnson, the Foreign Secretary and prominent 鈥淟eave鈥 campaigner, Sir Vince is expected to say: 鈥淎 disaster looms. Brexit. The product of a fraudulent and frivolous campaign led by two groups of silly public school boys living their dormitory pillow fights.鈥
He will add: 鈥淚n the real world, we have yet to experience the full impact of leaving Europe. But we have a taste of what is to come in the fall of the value of the pound.
鈥淔oreign exchange dealers are not point scoring politicians. Their cold, hard, unsentimental judgement has been, quite simply, that Brexit Britain will be poorer and weaker after Brexit than if we had decided to stay in Europe.鈥
He will accuse Labour of helping the Tories, saying they 鈥渓ined up behind Theresa May, maximising the chance of chaos and disruption鈥.
Sir Vince will offer to work with 鈥渟ensible grown-ups in the Conservative party and the Labour Party and the Greens鈥 to try to ensure the 海角视频 retains membership of the Single Market and Customs Union.
But he will also make it clear that the Lib Dems aim to prevent Brexit happening at all, saying: 鈥淥ur position is clear: the Liberal Democrats are the party of Remain.鈥
Setting out plans for a second EU referendum, he will say: 鈥淟et me be clear. This is not a call for a re-run 鈥 a second referendum 鈥 on Brexit.
鈥淚t is a call for a first referendum on the facts: when we know what Brexit means.鈥
Lib Dems have suffered a dramatic decline in their fortunes since being in Government as part of the Coalition government from 2010 to 2015.
They won just 12 out of 650 seats in June鈥檚 election, a far cry from the 57 seats they won in 2010.
