George Soros, the billionaire known as the man who “broke the Bank of England”, is backing a campaign to overturn Brexit, the Telegraph can disclose.

The investor is one of three senior figures linked to the Remain-supporting campaign group Best for Britain who plan to launch a nationwide advertising campaign this month, which they hope will lead to a second referendum to keep Britain in the EU.

The campaign is trying to recruit major Tory donors in an attempt to undermine Theresa May.

It also plans to target MPs and convince them to vote against the final Brexit deal to trigger another referendum or general election, according to a strategy document leaked from a meeting of the group.

Martin Sorrell, chief executive officer of WPP Plc, poses for a photograph following a Bloomberg Television interview on the closing day of the World Economic Forum (WEF) in Davos, Switzerland, on Friday, Jan. 26, 2018 credit: Bloomberg

The document says the campaign, which will begin by the end of this month, must “wake the country up and assert that Brexit is not a done deal. That it’s not too late to stop Brexit”.

It adds that a series of Momentum-style mass rallies and concerts are planned and the campaign will have a “heavy youth focus”. The memo also reveals a plan to “pressure” MPs in 100 Leave-supporting constituencies, and sets out how organisers “have a range of guerrilla marketing tactics” to build momentum.

Mr Soros’s involvement emerged after he entertained six Conservative donors at his Chelsea house last Monday.

His involvement comes more than 25 years after he made over £1 billion betting against the pound shortly before the UK withdrew from the European Exchange Rate Mechanism. More recently he has been accused of organising rallies against Donald Trump in the US and interfering in the democracies of several European nations.

Also at the dinner were Stephen Peel, a businessman and former Olympic rower who is also said to be putting money into the new venture and is on the board of Best for Britain; Lord Malloch-Brown, the former Labour minister and chairman of Best for Britain; and Sir Martin Sorrell, the chief executive of the advertising firm WPP.

A select group of Tory donors were also hosted by Mr Soros, who has donated £400,000 to Best for Britain through his Open Society Foundation.

The donors were told that the group’s goal was “to raise public support for Remain to a clear and growing national majority by June/July 2018 and channelling that pressure into MPs’ mailbags and surgeries”.

Lord Mark Malloch-Brown speaks to the press at a press briefing entitled "Business Engagement on the Sustainable Development Goals" at UN Headquarters in New York City credit: Getty

The document concludes that the movement “must then win the meaningful vote that Mrs May has promised on her Brexit deal in October” and adds that if she loses, “it is likely to trigger a new referendum, or election”.

“We must prevail decisively so reassuring Europe that our return will be permanent,” it states.

However, sources at the dinner said the message fell flat and the donors left without pledging any money.

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The campaign organisers have spoken previously of their desire for the UK to remain in the EU. Mr Soros said last year that Brexit was a “lose-lose proposition”, and Mr Peel has set out his vision for how Brexit could be overturned by gathering public support with concerts and rallies.

Neither Mr Soros nor Mr Peel responded to questions about their involvement in the campaign or dinner.

Lord Malloch-Brown hinted at his plan in an interview last year.

He said: “We need to sway public opinion nationally so that there is a majority to remain at the time of the vote in Parliament. We also have to lobby in constituencies in a targeted way so we are reaching Leave-voting MPs in constituencies where the majority voted Remain, and we have to work in constituencies where Remain MPs have been cowed by the support for Leave in their seats.”

Yana Peel (L) and Stephen Peel attend the Frieze Magazine 25th anniversary dinner at Brasserie Zedel on October 7, 2016 in London credit: Getty

The wording is very similar to the note circulated at the funding dinner.

On Wednesday night, Lord Malloch-Brown said that Best for Britain had declared all financial contributions and that Mr Soros had made “significant contributions to our work”.

Sir Martin has warned previously that Brexit has damaged the UK’s global reputation and was a vocal Remain supporter. He said that he was not involved in drafting the documents and his company was not “so far” expected to play any role in the strategies discussed.

EU commission President Jean-Claude Juncker (L) welcomes George Soros, Founder and Chairman of the Open Society Foundations prior to a meeting in Brussels, on April 27, 2017 credit: AFP

The memo also reveals that the group plans to provide financial support to European Movement, another campaign group which counts Stephen Dorrell, the former health minister, and Kenneth Clarke, the former chancellor, as chairman and vice-president.

Their inclusion in the strategy will raise questions about whether backbench Tory MPs are working against their party in a bid to block Brexit.

How MPs group chaired by Anna Soubry was given support worth £25,000 by Best for Britain anti-Brexit group

An MPs’ committee chaired by Anna Soubry was given support worth £25,000 by groups run by the figures at the heart of the campaign to overturn Brexit.

The All-Party Parliamentary Group (APPG) on EU Relations was given “secretariat support” worth up to £21,000 by Best for Britain, an anti-Brexit group. Best for Britain is the campaign name for UK-EU Open Policy Ltd.

Stephen Peel, a businessman who attended the dinner at George Soros’s home, has been a director of UK-EU Open Policy since it was set up in Oct 2016. Lord Mark Malloch-Brown, the former UN deputy secretary general, joined the organisation 13 months later, and sits on Best for Britain’s board.

Anna Soubry and Boris Johnson credit: i-Images Picture Agency

The APPG, which is co-chaired by Labour’s Chuka Umunna, was set up to “provide a forum for cross-party discussion on the UK’s relationship with the European Union”. It received support for “social media and correspondence” worth an additional £3,000 from European Movement, a group referred to in a leaked strategy document obtained by The Daily Telegraph.

Asked if it was appropriate for a Tory MP to oversee a group backed by Remain supporters intent on triggering an election, Ms Soubry declined to respond. But in a statement on the APPG’s behalf, Ms Soubry and Mr Umunna said it “complies with all the parliamentary rules governing APPGs”.

The document given to guests at "Brexit plot" meeting

The campaign relies heavily on launch advertising and free media to wake the country up and assert that BREXIT is not a done deal. That it's not too late to stop BREXIT. The first wave is planned for late February and is why funding is now so urgent. Like the campaign overall, the paid media will have a heavy youth focus. We will then move to constituency building activities through a combination of person-to-person campaigning and social media that pulls together stakeholders, including consumers, in sectors like the NHS, auto, aviation, pharma etc; again with a major youth push and other similar targeted activities. We have identified partner organisations in these sectors who will lead as we provide strategic, messaging, creative, social media and critically financial support. The partner organisations include unions, employee organisations, youth and consumer groups etc. Many are not exclusively Remain organisations but have wider community or industry interests which make them powerful third party endorsers of the Remain message.

We are also building a national field presence, concentrated on seats whose MPs needs [sic] to be brought into the Remain column by providing financial and other support to the European Movement, which has the best, but limited, current field presence of the Remain Groups.

We have a range of guerrilla marketing tactics in preparation to build early public impact by seizing attention and indicating a building momentum. A prominent Remain figure, Andrew Adonis, will brainstorm the top 100 leave constituencies. We are planning youth focused concerts and march combinations for the summer.

Our goals are to raise public support for Remain to a clear and growing national majority by June/July 2018 and channeling that pressure into MPs mailbags and surgeries,

We must then win the meaningful vote that Mrs May has promised on her BREXIT deal in October of this year. That is likely to trigger a new referendum, or election. We must prevail decisively so reassuring Europe that or return will be permanent.