The pro-euro campaign in Britain today published a letter from more than two dozen top business leaders urging Mr Tony Blair to call a referendum on euro membership.
Among those signing the letter are British Airways chairman Mr Colin Marshall and Vodafone chief executive Mr Chris Gent, as well as executives of Ford, Philips, BAE Systems, British American Tobacco, Unilever, WPP and Siemens.
The captains of industry also argued that inward investment into Britain had already fallen substantially.
They cited figures from the United Nations showing that Britain's share of foreign direct investment into the European Union had fallen to 16 per cent since the launch of the euro in 1999, from 29 per cent during the 20 years to 1999.
The main anti-euro grouping, the No Campaign, dispute these figures, which they say are flawed, partly because they overlook inward investment from fellow EU members.
The grouping also argues that two-thirds of British businesses want to keep the pound, citing a poll conducted by ICM in September 2002.
The open letter to Mr Blair comes less than four weeks before a deadline set by the Labour government for a decision on whether its five self-imposed economic tests for switching to the euro have been met.
A positive verdict, seen as unlikely, would lead to a public referendum on the issue.