THE nation can rest easy. The twinkle-toed Sir Vince Cable has not – unlike others at Westminster - abused drugs, hard or soft.

But his new protégé, the silky smooth Chuka Umunna, confirmed that he had enjoyed the occasion cannabis puff in his younger days.

The “well did you?” question - that is now a regular feature at press conferences post the Gove revelation - was answered with Mr U saying: “In relation to the mandatory drugs question, I have admitted to smoking cannabis, weed, but I have never taken any other drug; I certainly haven’t taken cocaine.” He snipped: “Maybe Boris Johnson will answer that question one day.”

But then Vince butted in to laughter: “You haven’t asked me.” The 76-year-old outgoing leader fessed up to being squeaky clean, describing himself as an “extreme puritan”.

The presser was hurriedly called because of the former Labour, former Change UK, former Independent MP had decided his natural home was now within the arms of the yellow peril.

His Lib Dem baptism took place at a conference room in the rather swish surroundings of the old Transport House in London’s Smith Square – the onetime home of Labour and the T&G union.

Reverend Vince addressed the congregation, insisting the new arrival was a “big political personality” and, despite previous differences, was now a lovely bouncing social democratic Liberal.

Indeed the outgoing king suggested other ex-TIGers might be about to start adding yellow to their wardrobe.

Of course, things were not so nice when Chuka was Labour’s frontbencher, trading “fairly heavy blows” with the Business Secretary in the Lib-Con coalition: Sir Vince. Since then in various tweets he has branded the Lib Dems "untrustworthy".

But the pro-PR, pro-federalism, pro-Remain Chuka spoke of his “political journey,” describing himself as a “social democrat with liberal values” and insisted he was neither tribal nor a careerist.

“This hasn’t been about some kind of career move and becoming the leader of any party. I’m not applying to be leader of the Liberal Democrats, that’s not what this is about.”

Ed Davey, Jo Swinson’s rival, sitting in the front row, thought: “Phew. Thank God for that.”

Mr U insisted his switch was all about values. He made clear he would be staying as a candidate in London's Streatham, if the local party chose him; rumours have started when Sir Vince stands down, the Twickenham candidacy could be handed over to the new boy, who is already being regarded by some as a Lib Dem leader-in-waiting.

Chuka insisted that as a one-day-old Liberal he would not be so “arrogant and presumptuous” to back Ed or Jo in the leadership contest. But party sources are speculating he will become its Treasury spokesman come the summer.

On the way to the Umunna baptism, I suggested to a Lib Dem peer that if only Chuka had jumped ship a year ago, he might now be in the running to be the party’s leader. “A year ago?” asked his lordship. “A week ago!”