New hard-line proposals, discussed by Cabinet ministers last week, are winning the backing of leading centre-left figures as well as Eurosceptics. Stephen Dorrell, Secretary of State for Health, and Malcolm Rifkind, the Foreign Secretary are now seen as hawks who are willing to obstruct the EU's Inter-governmental conference.
The tougher approach, which pro-Europeans see as new evidence of a move to the right in the Conservative Party, may be revealed this week if a meeting of the EU veterinary committee on Tuesday fails to lift bans on British gelatine and tallow.
Evidence of a shift in government thinking towards the sceptics came as Labour leader Tony Blair appealed to left-wing Conservatives to join his party.
In an interview with today's Observer he said: "It will be very difficult for many [Tories] to be virulently opposed to a Labour government." He claimed that left-leaning Conservatives "have got a lot more in common with us than they have with those who have taken over their own party".
The heads of government meeting in Florence on June 21-22 is seen as a key point for a show-down with EU partners, unless progress has been made. The Cabinet is attracted to a strategy under which Britain would simply refuse to give in, digging in for concessions as Margaret Thatcher did over the EU budget in the early 1980s. This is seen as preferable to boycotting EU meetings - the so-called "empty chair" strategy.
One source commented: "Stephen Dorrell is hard-nosed about it all. Malcolm Rifkind invites a greater range of options than his predecessor [at the Foreign Office], Douglas Hurd, and those options are inclined to be tough."
However Kenneth Clarke, the Chancellor, is resisting any hardening of the position which, he argues, could undermine Britain's international position in the long term - particularly if John Major's bluff is called. Earlier suggestions that the Government might retaliate by banning some European produce resulted in a humiliating retreat for the government.
In today's Sunday Times, John Major hardened his Eurosceptic rhetoric. He warned he will "stand up for British interests" at the Inter-governmental Conference, on June 21-22, that "we will most certainly use the veto" and promised no return to an exchange rate mechanism.
The hand of those pressing for a tough new stand may have been strengthened by last Thursday's local election results, which were slightly better for the Government than forecast. Sceptics argue that some voters are blaming Europe, and not the Government, for the beef crisis.
One right-wing Government source was enthusiastic about disrupting the EU Inter-Governmental Conference (IGC) in Italy. "What do we have to lose in saying: 'There is going to be no IGC until we have sorted this out?' " he said.
More significantly, anger with Brussels has spread beyond traditional sceptics. One pro-European ministerial source said: "If we do not get movement it will reinforce people's irritation about this, and that goes across the party, not just the sceptics who will be irritated anyway. That message will be conveyed at a very high level to foreign governments."
Downing Street is conscious of the risks attached to such a strategy, but Mr Major is determined not to repeat his experience at the last summit in Turin, where other leaders expressed sympathy and support for Mr Major's plight - but then failed to assist in lifting the beef ban.
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