He said his youth supporters were “very active and fighting the Brexit war,” and made clear his plot to mimic Labour’s army of young foot soldiers.
In an interview with The Sunday Times to mark the Lib Dem’s 30th anniversary, he added: “The Labour party started out with a good idea but it became a ramp for a takeover by revolutionary hardliners.
“But we have the youngest membership of all the major parties. We have 100,000 members.”
Asked what the point of the Lib Dems was now they are dwindling to single digits on opinion polls, Mr Cable boasted Labour MPs would jump ship.
He said: “People are underestimating the extent to which Brexit will shake up British politics. There is a deep, deep unhappiness among large numbers of Labour MPs and activists and at some point something is going to give.
“Before very long you will see a fair number of Labour MPs and other activists removed or removing themselves.”
He added: “I’ve made it very clear we wouldn’t want to work with them if they found themselves in that position.”
He also plans to cash in on Brexit.
He said: “On the big issue of this generation, we are the only party which is arguing the case for Remain.
“I think we will eventually be vindicated. We opposed the Iraq War from the beginning but we were vindicated.”
He added: “I think the same will happen on a bigger scale with breed.”
Mr Cable said the Lib Dems could boost their following in May’s local elections by targeting the 1million EU citizens who can vote.
In an effort to prove his party still had radical ideas, he said it was determined to scrap Ofsted in favour of school tables that took pupil wellbeing into account, as well as exam results that he said had created “a Dickensian approach to education”.
Mr Cable admitted their pledge to drop tuition fees before the 2010 election as “rather foolish”, adding it had “done a lot of harm” when in the coalition with the Tories.
But he said he backed a graduate tax and would reintroduce maintenance grants.