Labour MPs are generally said to be more pro-European than Conservatives, but the survey highlights the scale of dissent that Tony Blair will have to face if he becomes prime minister.
The findings show that Labour MPs are evenly divided over giving further powers to EU institutions, and a strong anti-European hard core - 21 per cent - believes that a single European currency would mean "the end of the UK as a sovereign nation".
The sensitivity of the study is underlined by the fact that Labour whips ordered MPs not to take part as soon as they heard it was under way. But the research team, led by Professor Andrew Gamble of Sheffield University, still managed between November 1995 and February this year to interview a politically balanced sample of a third of Labour MPs - including frontbenchers. Two years ago, Professor Gamble, a leading political scientist, produced a survey of Tory MPs which showed the depth of their hostility to the EU, and which drove John Major to a more sceptical stance.
The new study suggests that opposition to a single currency extends well beyond Labour's hard core. By a margin of 42 to 38 per cent, with 20 per cent undecided, Labour MPs agree that "Britain should never permit its monetary policy to be determined by an independent European Central Bank" - a condition of the single currency under the Maastricht Treaty. The figures imply that Mr Blair could face serious opposition from a coalition of Euro- sceptics and traditionalist supporters of reflation if he seeks to take Britain into a single currency in the next Parliament.
Mr Blair may also face difficulties if Labour is in power when the Inter- Governmental Conference (IGC) to revise the Maastricht Treaty concludes - almost certainly after the British general election.
Asked if the IGC should increase the supranational powers of EU institutions, 38 per cent of Labour MPs agreed and 38 per cent disagreed, with 24 per cent undecided.
The survey also suggests a gap between opinion on the back benches and among Labour shadow ministers, which could pose dangers to a Blair government. Although 28 per cent of backbenchers think a single currency means the end of the UK, for example, none of the frontbenchers agreed.
Another split is between older and younger MPs. In contrast to the Tories, Labour is becoming more pro-European, as a more EU-minded generation takes over. None of the 1987-1992 intake, for example, wants Britain to withdraw from the EU, against 15 per cent of older MPs.
The survey confirms the historic switch between Labour and Tory parties, with the Tories now markedly more hostile to the EU than Labour MPs.
While 28 per cent of backbench Labour MPs said the single currency would mean the end of the UK as a sovereign nation, just over 50 per cent of backbench Tories agreed in the survey carried out two years ago.
Thirty per cent of Labour MPs agree "sovereignty cannot be pooled", but 60 per cent of Tories agreed.
And only 18 per cent of Labour MPs want an "Act of Supremacy" to assert explicitly the ultimate power of Westminster over EU law - compared with 56 per cent of Tory MPs two years ago. (The Labour figure falls to 7 per cent among new MPs - those elected in 1987 or 1992 - and to zero among frontbenchers.)
Only a quarter of Labour MPs back the extreme Euro-sceptic demand that the European Commission should lose the right to initiate legislation - a position held by 61 per cent of Tories. Unlike the Tories, most Labour MPs have no objections to a single European army, although they want to retain Britain's veto in foreign and defence policy.
The survey suggests that Labour divisions could have influenced Mr Blair's decision not to match John Major's promise of a referendum on a single currency. While Labour backbenchers support the idea by 56-34 per cent, frontbenchers are opposed by 50-35 per cent.
The Labour leader has not yet decided what his attitude to a single currency will be, should he be in government and Germany and France decide, early in 1998, to launch it on the Maastricht target date of 1 January 1999. Selling the idea to his MPs will be crucially dependent on economic circumstances, because nearly 80 per cent of Labour MPs say the UK should not seek to meet the convergence criteria "if the result is increased unemployment in Britain". And 31 per cent of backbenchers say "a single currency as set out in the Maastricht Treaty will institutionalise neo-liberal economic policy".
Professor Gamble and Steve Ludlam at Sheffield, and David Baker and David Seawright at Nottingham Trent university interviewed 90 of Labour's 271 MPs (now 272 after the Staffordshire South East by-election), including 29 frontbenchers.Reuse content