The time is now,” said Lord Malloch-Brown, the former Labour minister, as he concluded his presentation. But he had misjudged his audience. The Conservative Party donors he was addressing had little interest in his proposal: a plan to stop Brexit by bringing down the Government.

Malloch-Brown’s presentation – made on Monday last week, at dinner at George Soros’s house in Chelsea – described the strategy for Best for Britain, the campaign group he runs, which was established by Gina Miller to fight Brexit. Their campaign, due to launch at the end of this month, will be funded by Soros, the billionaire investor; Stephen Peel, a private equity investor; and others.

It will begin with an advertising blitz targeting younger voters, and continue with traditional and social media campaigning. There are plans for “guerrilla marketing tactics”, as well as “youth-focused” concerts and marches.

There is a proposed partnership with trade unions, employer bodies, youth groups and consumer organisations. These groups will adopt seemingly independent public positions opposing the Government’s Brexit plans, but Best for Britain will provide them with “strategic, messaging, creative, social media and critically financial support”.