Labour Party leaders last night came to the sensible conclusion that it was not worth splitting the Labour movement wide open over the Common Market when Mr Heath and the Conservative Party were already faced with the even more immediate and difficult problem of rallying a respectable Parliamentary majority for entry on the basis of Tory votes without the aid of Labour MPs.

That was, to all intents and purposes, the outcome of a full afternoon session of Labour’s national executive committee and the Shadow Cabinet of the Parliamentary Labour Party, at which Mr Wilson and Mr Callaghan succeeded in persuading both pro- and anti-Market groups not to insist on firm decisions on either tactics or principle. For the time being, the heat is out of the European issue inside the party.

Talking across a green baize table the size of a tennis court in British Rail’s unhived-off Great Western Hotel, Mr Wilson told the joint meeting that he did not believe Mr Heath would recommend acceptance of any foreseeable entry terms unless he was confident that he could achieve a clear Commons majority based on Tory votes unaided by Labour pro-Marketeers.

Mr Heath, he added, was a politician too. Though a keen European, he liked being Prime Minister, and had no desire to give up the job for Europe or anything else.

The implication was clear and was well taken in the meeting: Mr Heath has his problems and should not be helped out of them by precipitating the type of split which kept Labour out of office throughout the 1950s.

Mr Wilson was summing up an entire day’s debate, most of which had been devoted to Europe and the Common Market. He listed four possible courses which events might take as a result of Britain’s negotiations with the Six, measuring them against the fact that Labour’s NEC had not only decided that there should be a special conference of the Party on Europe, but had even made a provincial booking in London for July 24.

The first, he said, was that Mr Heath might call for a vote on the terms in the Commons in July before the provisional date for Labour’s conference. This, he said, was unlikely since the Conservative Party also needed time to rally its backbenchers.

The second was that Mr Heath might decide upon a non-committal Commons debate in July based upon a simple “take note” motion involving no on-the-spot decision. If such a debate took place before Labour’s special conference, he said, the party’s front bench spokesmen would have to confine themselves to probing and questioning, without taking a positive line, until the party had had its say.

City workers studying newspapers reporting the Commons vote on Common Market entry, 29 October 1971. Photograph: Douglas Miller/Getty Images

The third was that Mr Heath might, if the terms were especially tough, confine himself to the publication of a White Paper which set out the conditions of entry without taking up a definitive line. Even the Government, said Mr Wilson, might find itself unable to make up its mind.

But, Mr Wilson went on, it would be a mistake to forget the possibility that Mr Heath might decide, after looking at the terms, that they were so impossible that he could not recommend them to his party, let alone the country.

Mr Wilson ended by repeating words he had used about his own negotiations for entry – that Britain was strong enough to stand on her own feet if she failed to get into Europe. He added a final plea for his own equivocal stance: “We don’t know the terms and we don’t know the timing. The Shadow Cabinet line has still not been decided. How can we decide without knowing the terms?”

Earlier, Mr Wilson had raised a laugh by remarking that he seemed to be the only person in the party who was sticking to the party line by waiting for the terms. He was commenting on references in the debate to the 100 pro-Marketeers (including the party’s deputy leader, Mr Jenkins, and six other shadow Ministers) who had signed an advertisement in the Guardian and 120 anti-Marketeers who had signed a Commons motion opposing entry on any probable terms.

These and other issues were raised in a remarkably relaxed and unfraught debate, by the standards of similar meetings on earlier occasions. Indeed, it was Mr Jenkins and his fellow pro-Europeans who pleaded for unity, brotherhood, and a respect for the opinions of others.

They did so as part of an appeal for a free vote, untrammelled by a party whip, when the Commons finally comes to divide on the issue. As Mr George Thomson, a former Foreign Office Minister argued, it would be better if the party did not tear itself apart.

Mrs Castle and Mr Peart, both committed anti-Marketeers, replied that they could not see how the party could fail to adopt a positive policy towards Europe if it claimed to be the alternative Government. But they accepted that there had to be respect for the views of those who could not accept the party line, and Mr Michael Foot added that there should be no question of expulsions or witch hunts for those who failed to obey a party whip.

But it was Mr Wilson who put an end to discussion of this thorny problem. He pointed out that the joint NEC/Shadow Cabinet meeting had no authority to make a decision on how members of the Parliamentary Labour Party should vote.

There were also some entertaining asides in the confused and inconclusive debate. Mr Harold Lever, a noted parliamentary wit with strong European views, remarked that he did not see why MPs should not sign motions on such an issue. “I can’t understand why political animals should be criticised for taking political action,” he said.

And Mr Anthony Crosland, the Shadow Secretary for the Environment, used the recent mark crisis as an example of the degree of sovereignty still available to EEC members. West Germany’s action in floating the mark had demonstrated that member countries could still act independently, he said.

Mr Foot replied that it seemed a strange point of view to argue that the fact that the Germans had broken the rules made the Treaty of Rome more acceptable.

The morning session of the meeting had begun with a discussion of the work being done on future party policy by various policy committees. It was notable for a warning from Mr Wilson that a party could have all the policy committees it liked in opposition, but was still liable to be overtaken by international financial and monetary events which prevented it doing what it intended to do. More would have to be done to get on top of the “casino aspects” of the economy like the banks and the Stock Exchange, he said.

But the most powerful appeal for a return to traditional Socialist ideals came from Mr Houghton, the chairman of the Parliamentary Labour Party. He argued that it was no good appealing to the electorate by claiming that Labour could meet the acquisitive desires of the public better than the Tories. That course could only lead to disillusion.

What was needed was a restatement of the true aims of the movement. The party should ask itself whether it was trying to make more Socialists, or merely trying to get more votes, he said.

The meeting is due to continue this morning, when it will consider issues relating to incomes policy and industrial legislation postponed from yesterday’s session because of the Common Market debate.