Meanwhile, Kenneth Clarke, the Home Secretary, insisted that the cross-party battle over the Bill to ratify the treaty must be fought on clear political lines, not technicalities - a statement that could be interpreted as a warning both to his ministerial colleagues and to unruly Tory backbenchers.
The warning, the latest round of interpretation and counter-interpretation over developments on the Bill, coincided with a wave of accusations that the Prime Minister might attempt to sideline Parliament by using the Crown Prerogative to ratify the treaty, regardless of the fate of amendment 27, Labour's attempt, supported by the Liberal Democrats, to reverse the Social Chapter opt-out.
They came after weekend reports of a legal opinion advising the Government that ratification of an international treaty was an executive act that did not require Parliament's consent.
As pro- and anti-MPs of all parties, including the Ulster Unionists, expressed outrage at the possibility of the treaty (minus the opt-out) being ratified 'at the stroke of a pen' or by 'trickery', Mr Clarke, speaking before the question of Royal Prerogative was mooted, called on his own party's rebels to call off their 'accidental' alliance supporting Labour's amendment on the Social Chapter. He called the Government's opponents an 'ill-assorted' collection whose views were supported by the 'hysterical' language of Lord Tebbit.
Mr Clarke dismissed the row over the Social Chapter as a 'mini-problem'. In common with Whitehall sources, the Home Secretary emphasised that last week's statement by Douglas Hurd, the Foreign Secretary - that there was no question of the Government ratifying a treaty other than the one we negotiated - was unsurprising and uncontroversial.
Denying that Mr Hurd had, in effect, threatened to withdraw the Bill if the amendment succeeded, so giving succour to the Tory rebels, Mr Clarke said the comments had been a 'clear restatement of government policy'.
Foreign Office sources also denied any shift of tactic in favour of resorting to the prerogative to side-step parliamentary opposition.
The effect of a successful amendment 27 is unclear because while it removes the UK's permission to opt out of the Social Chapter, it does not commit Britain to signing up for it.
Mr Clarke sought to brush aside those technical uncertainties in a BBC television On the Record interview. 'The politics I think is clearer than the law. The politics is that it is essential for this country to ratify the Maastricht treaty if we're to continue to be a full participating member in the Community, to have the influence over the single market we want.'
The Social Chapter represented the kind of single market the Government did not want, he said.
Mr Clarke said that since the Government had been so clearly against the chapter, it could not 'reputably' ratify the treaty if, by some contrivance, it was faced with the chapter's inclusion. 'What we will do is win this vote by confronting our ill-assorted opponents with the reality of what they're doing.
'It's the task of government to sort out these opponents and, more importantly, sort out our supporters, to make sure we get the majority.'
But one leading Tory backbencher indicated worse trouble ahead for the Government yesterday. The pro-European Michael Ancram, MP for Devizes, told the programme: 'If the failure of Maastricht meant that the European Community as such began to unravel . . . I think I would have to vote for Maastricht and the Social Chapter and I think an awful lot of people would feel the same.'
Even Mr Clarke was not averse yesterday to the technique of the dire warning. He said: 'The whole Maastricht agreement was a compromise of national interests . . . If you go back to an inter-governmental conference and say we, the British, now wish to alter a particular part of it, you will find that several other member states will be compelled to open issues up as well.'
Letters, page 18
Gavyn Davies, page 21Reuse content