British business needs a clear statement of intent from the government over the euro, a leading businessman has warned.

Speaking in Brussels, Niall FitzGerald, the chairman of Unilever, demanded a definitive timetable on euro entry, even if the chancellor rules out the single currency at the present time.

FitzGerald called for clarification of government intentions to give business "the certainty to plan, the stability to grow and the competitive environment in which to shine".

Pro-euro business leaders are desperately seeking to keep the door open to a referendum on the single currency within this parliament.

But the signs coming from the Treasury are that Britain does not currently meet the chancellor's five economic tests.

Despite this assessment, supporters of the euro claim that failure to enter into the single currency in its formative years will leave the British economy the "loser" in the long term.

Addressing CBI colleagues FitzGerald said: "We all know that the economic conditions for Britain's entry are not perfect...but they never will be.

"That the risks inherent in joining have not all been removed...but they never will be. And that the guarantee of winning a referendum does not currently exist...but it never will."

He will also ask the prime minister to follow his "instincts" and lead Britain into the euro.

"A decision to delay further will satisfy no-one. The British people will be cynical. Our European partners will feel let down. And British business - I would suggest - will be unforgiving."

Pro-European groups fear that a negative outcome of the June 9 assessment will prove to be a fundamental setback in Britain's relations with Europe.

"If Britain once again fails to take the path so clearly laid out, if we fail to enter the next phase of Europe's development at a crucial and formative stage, then we will all be the losers.

"Trade will suffer, investment will suffer, and our influence will suffer.

"Of course, none of us knows for sure what will be said on June 9.

"But I do hope - and I fully expect - that at the very least, the very least, the government will provide a clear timetable and a specific action plan for demonstrating how it now intends to achieve economic convergence."