The Cabinet minister implored colleagues not to “visit harm” on families in Britain, who could lose their work, by pursuing a policy leading to a disruptive crash-out from the EU which would see new trade tariffs and barriers.
Tory leadership frontrunner Boris Johnson and his rival, Foreign Secretary Jeremy Hunt, have both said they are prepared to take the UK out of the European bloc with No Deal if no agreement can be reached with Brussels.
Around 30 Tory MPs, including the current Chancellor Philip Hammond, have signalled that they are ready to fight in Parliament against such a severe departure from the EU.
“It’s evident that if you have the disruption that comes from a no-deal Brexit there will be people that will lose their jobs,” Mr Clark told Sky News.
“It’s many thousands of jobs. Everyone knows that.”
Mr Clark, who has heard a wave of warnings from business chiefs about the potential impact, added: “Everyone accepts this is a very difficult challenge. When the country voted to leave the EU of course there is a requirement to implement that but I think we need to do it in a way that takes full account of the impact on real people’s lives and do everything we can to ensure it doesn’t visit harm on them.”
His warning came ahead of Mr Johnson and Mr Hunt facing grillings by the BBC’s Andrew Neil in interviews to be aired this evening.
They will also take part in the latest hustings of Tory members in Cheltenham.
Mr Johnson has pledged that the UK must leave the EU on October 31, with or without a deal, while Mr Hunt has avoided such a hard deadline.
Theresa May told today of her dismay that Brexiteers had sunk her plans to quit the EU.
“I had assumed mistakenly that the tough bit of the negotiation was with the EU, that Parliament would accept the vote of the British people and just want to get it done, that people who’d spent their lives campaigning for Brexit would vote to get us out on March 29 and May 27. But they didn’t,” she said in an interview with the Daily Mail.
Tory MPs opposed to a No Deal are reportedly threatening a “sit in” if there is an attempt to prorogue Parliament to force through such an exit from the EU.