Civil servants are "mentally" carrying out work on a possible British exit from the European Union in spite of ministers' insistence that no contingency planning is going on, former Cabinet secretary Lord O'Donnell has predicted.
The government has pledged to hold an in-out referendum on Britain's membership of the EU by next year. But Number 10 has said that officials are not drawing up plans in preparation of voters opting to leave the bloc.
However, Lord O'Donnell, who served as cabinet secretary from 2005 to 2011, told the BBC that he believed civil servants would be informally working through the implications of a vote for "Brexit".
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"Every single civil servant will be thinking ‘what if, what are the different possibilities, different scenarios’ and I will be absolutely sure that they will be hoovering up all the work that is done by the outside world and the Foreign Office," he told the BBC.
"This is something that they will be thinking about, their lawyers will be thinking about, the economists will be going through, we know they will have to do work on trade, migration, so think there will be a lot of work going on mentally.
"How much they write down is a different question – that is one of the potential drawbacks of the world of Freedom of Information that we live in that actually if the chancellor does not want anything written down then that is the way that it will be.”
And he added: "We need to be like boy scouts – ‘be prepared' is the key – so I think they will be thinking through the various scenarios and of course they have got some time.”
A spokesperson for the Cabinet Office said the civil service was "working round the clock" to support the prime minister's strategy of renegotiating key elements of the UK's relationship with the EU.
Last week, David Cameron announced that Cabinet ministers who choose to campaign against the government's official position on the EU vote – expected to be in favour of the UK staying in a reformed Europe – will not be able to draw on the support of departmental civil servants to do so, relying instead on their own politically-appointed special advisers.