Major showered with referendum advice: Patricia Wynn Davies reports on the exchanges intensifying the Europe rift

DOWNING STREET'S reluctance to rule out decisively the notion of a referendum on more European integration was more than matched yesterday with a plethora of advice for the Prime Minister from the Conservative backbenches.

As Norman Lamont, the former Chancellor, and Lord Parkinson, the Thatcherite former party chairman, swiftly endorsed such a move, Bill Cash, de facto leader of anti- Maatricht backbenchers, insisted that it should not await the Inter- Governmental Conference in 1996 but follow as soon as possible after the European elections.

It was left in the main to the Labour leader, John Smith, to downplay the issue, saying 'this is an issue so far ahead that we can consider all these matters carefully much nearer the time'.

Paddy Ashdown, the Liberal Democrat leader, was seen by some Tories yesterday as having seized the initiative with his weekend manifesto pledge that the public should have a say over any substantial further constitutional changes produced by the 1996 conference.

In radio and television interviews, Mr Lamont sought to hammer home his backing, insisting there was a growing body of support 'on all sides'. He was 'not so sure' that the Prime Minister was absolutely against one.

As it declined yesterday to reject all future possibility, Number 10 implicitly echoed that view. The fact that more Euro-sceptical Cabinet ministers such as John Redwood, Secretary of State for Wales, declined to rule out the idea at the weekend was also left hanging, in contrast to the stronger line recently taken against Michael Portillo's remarks over the single currency. There had been 'huge exaggeration' over alleged differences between Cabinet members' views.

Officials went out of their way, however, to emphasise the position on the single European currency, which was already covered by the Maastricht treaty opt-out and by a pledge that the UK would not enter it unless and until Parliament approved it.

At this juncture, any promise of a referendum on that issue remains a remote prospect.

While playing down the need for the Government to change its position, even Tristan Garel-Jones, the former Foreign Office minister who piloted Maastricht through the Commons, said he had always been 'sneakingly tempted' by the idea because it would produce the same result as in 1975 - when Harold Wilson broke with centuries of constitutional convention and called a referendum in an effort to unite a deeply divided Labour Party.

Most Tory Euro-supporters were against the idea, fearing the thin end of the wedge. Some Euro- sceptics have made clear that their ultimate aim is to get John Major to rule out any prospect of a single currency. But Peter Temple-Morris, MP for Leominster, one of the party's most convinced Europhiles and enthusiastic backer of Michael Heseltine for party leader, told BBC radio: '1996 could be a general election year here. It is also intergovernmental conference year. I think we may well have to keep the option open of having a referendum in connection with 96, either before on the basis of what we go there with, or after it on the basis of what we come back with.'

There was little doubt yesterday that a number of Tory backbenchers see a referendum as a way of lowering the temperature and avoiding the deep party division that is now being openly warned of by Euro- sceptics.

Rhodes Boyson, the Euro-sceptical MP for Brent North, urged the Government to 'give a pledge, within 48 hours, that the removal of any more power to Brussels should be put to a referendum'.

Dr Boyson added that Mr Ashdown's decision to back a referendum over any further integration - reached by the Liberal Democrat leader in the early hours of Saturday morning - had 'trumped our ace'.

There were some warnings of short-termism, however - with one senior Tory declaring: 'You still have to decide the policy.'