On Thursday morning, Sky News reported that “dozens” of FTSE 100 companies – including Barlcays, HSBC, Unilever and Legal & General – are readying formal announcements should the Conservatives win in the 2015 General Election, and push ahead with plans to hold a vote on the UK’s continued membership of the European Union. The firms in question are said to be in talks with auditors and lawyers while drafting their statements, and will issue them later this year.

Two years ago, David Cameron promised to hold a referendum on Britain’s EU membership by the end of the 2017 – however, in January this year, the Prime Minister said the date could be moved forward if the Conservatives form the next government after the 7 May election.

Moody’s has also announced that a ‘Brexit’ would inevitably damage the UK’s credit rating – and cause far more damage to Britain’s standing than the temporary uncertainties over the form of the next government – due to the negative consequences for trade with and investment from continental partners.

“The EU accounts for around half of the UK’s goods and 36 per cent of its services exports,” a spokesperson for the agency said, “and a withdrawal from the EU could have negative implications for trade and investment, both ahead of the event and following it.”

Moody’s further expressed concern over Cameron’s pledge to renegotiate the terms of the UK’s EU membership, warning that a failure to maintain comparable trade terms would compel the agency to re-analyse its growth prospects.