A business leader has waded into the row over the UK's involvement in Europe by warning of the risks to British industry of "isolation".
CBI president Sir Roger Carr pointed out that Europe accounts for half of British exports, telling firms that while they should look for new partners, they must not forget "old friends".
Opening the CBI's annual conference in London, Sir Roger, chairman of energy giant Centrica, said: "Whatever the popular appeal may be of withdrawal, businessmen and politicians must keep a bridge firmly in place. As countries of Europe bind together in pursuit of salvation, we in the UK must work harder to avoid the risks of isolation."
Labour leader Ed Miliband will tell the CBI conference later that pressure on David Cameron from eurosceptic Tories had forced the Prime Minister into "negotiations that will not deliver" for the repatriation of swathes of powers.
Instead he should be concentrating on "building alliances" to agree reforms and ensure Britain does not lose out when eurozone countries deepen their ties in a new two-tier Europe, he will suggest.
Weekend opinion polls showed a clear public majority for cutting ties with Brussels as pressure mounted on the Prime Minister to set out plans for a referendum on the issue.
Veteran Cabinet pro-European Ken Clarke said it would be a "disaster" for Britain if it left the EU. He said the UK's negotiating position was being undermined by the "irresponsible" debate about its continuing membership.
Writing in his column in the Daily Telegraph, London Mayor Boris Johnson said the Prime Minister would be right to veto the EU spending package when he attends a summit this week.
"It may be impossible to cut the budget, since there is no other country actively proposing this excellent option. But there is no reason at all why EU spending should not be frozen exactly where it is. The worst that can happen is that the existing budget will be rolled over, a month at a time.
"It is time for David Cameron to put on that pineapple-coloured wig and powder blue suit, whirl his handbag round his head and bring it crashing to the table with the words no, non, nein, neen, nee, ne, ei and ochi, until they get the message."