Britain must be ready to leave the European Union to boost its competitiveness in the global market, according to Digby Jones.
Lord Jones of Birmingham - who as Digby Jones was director general of the CBI - warned that the EU was a "job destroyer" and that Prime Minister David Cameron's promised renegotiation of Britain's membership was unlikely to achieve more than "minor adjustments" to its system of regulations and subsidies.
He called for a referendum on UK membership to be staged "as soon as possible", rather than held back until 2017, after a post-election renegotiation, as Mr Cameron plans.
His comments stand in stark contrast to the current views of the CBI, which this week issued a strong case for the UK remaining in Europe.
Writing in the The Times, Lord Jones said: "We are faced with an unelected ruling elite in Brussels that still can't balance its books, where the culture is still one of marching valiantly towards 1970 and where criticism is condescendingly seen as heretical.
"The Prime Minister's plan to negotiate reform and then ask the British people to affirm or reject continuing membership would create a long period of uncertainty for business. It would be better to hold a referendum as soon as possible and end the uncertainty.
"David Cameron will get minor adjustments here and there but he won't get the sort of reform upon which our future membership should be conditional. If anyone, the CBI included, thinks that fundamental reform is on the EU agenda, they are deluding themselves."
Leaving the EU would not be the "unattractive option" that pro-Europeans claim, as the UK would be able to put free trade agreements in place with the rest of the bloc "the day after our exit", he said.
"We certainly must put the option of leaving on the negotiating table," he said.
"The tactic of promising to stay in the EU regardless of what the Prime Minister can negotiate is insane. When did anyone start negotiations with 'It's OK, we don't mean it, we will do what you want anyway' as an opening gambit?"