EU referendum: Leaked letter 'shows how Cameron plotted against Leave'

PM accused of being 'knee deep in conspiracy' for Remain while his official position was that he could still campaign for Leave if his renegotiation failed

Prime Minister David Cameron stands with Boris Johnson as the Olympic cauldron is lit for the Paralympic Games in Trafalgar Square on August, 2012 (Getty)

The Vote Leave campaign has accused David Cameron of being “knee deep in a conspiracy” to keep Britain in the EU, as letters emerged indicating the Prime Minister discussed the role big business could play in the Remain campaign before he had even completed his renegotiation deal with European leaders.

In a letter to Mr Cameron from Serco chief executive Rupert Soames, sent 11 days before the renegotiation deal was completed, and the EU referendum formally announced, the business leader refers to talks held with the Prime Minister earlier in the month.

He writes that, following up on the meeting, he is planning to contact FTSE 500 companies to urge them to mention the risks of Brexit in their annual reports.

At the time of the meeting and the letter, dated 8 February, Mr Cameron’s official position was that he could still campaign for a Leave vote if his renegotiation failed to secure the changes he wanted.

He told the House of Commons on February 3: “I am not arguing – and I will never argue – that Britain couldn’t survive outside the European Union…If we can’t secure these changes, I rule nothing out.”

However in the letter, seen by the Daily Mail, Mr Soames states: "There were two points I thought I might follow up on. The first is how to mobilise corporates to look carefully at the risks Brexit represents.

"I am working with Peter Chadlington and Stuart Rose [head of the Britain Stronger in Europe campaign) with a view to contacting FTSE 500 companies who have annual reports due for publication before June and persuading them that they should include Brexit in the list of key risks. All public companies are required to set out in their annual report an analysis of key risks."

Labour MP Gisela Stuart, chair of the Vote Leave campaign, said the Prime Minister had “serious issues” to answer.

“We now know he has been doing deals with businesses to exaggerate the risk of a vote by the UK to leave the EU,” she said. “He must now tell us urgently how many businesses he cut secret deals with? Who are they and what were they promised in return?”

Downing Street said it did not comment on leaked documents.

Many Westminster observers doubted at the time that the Prime Minister was seriously considering backing a Leave vote, but the timing of the leaked letter will be embarrassing to the Remain campaign, coming a day after George Osborne mocked Brexit campaigners as conspiracy theorists.

Ms Stuart added: “George Osborne accused the Leave campaign of inventing conspiracies. Now we see that David Cameron is knee deep in one.”

Mr Soames is the brother of Tory MP Nicholas Soames, and a grandson of Sir Winston Churhcill. His brother Nicholas has been an outspoken supporter of the Remain campaign. Serco, a security firm which has a number of contracts with the Government and EU institutions, was one of 200 companies to sign a letter backing EU membership later in February. The firm denied there was any link between its support for EU membership and efforts to secure public contracts.