David Cameron has produced a European policy which should prevent his party from splitting over its most divisive issue. He should be congratulated for his obfuscation.

By Alex Stevenson

The Tory leader faced a tough challenge today. The pressure was on to produce a new policy which could keep his party together, especially after a prime minister's questions when his previous "cast-iron" commitment to holding a referendum on the Lisbon treaty came back to haunt him. The Conservatives are, at their core, as fundamentally divided on Europe as they have ever been. Lisbon's ratification risked disturbing a sleeping monster which has for so many years threatened to tear the party apart.

What Cameron has come up with is sufficiently vague that even ardently Europhile Tories can toe the line. The proposal for a "referendum lock" would see future treaties requiring the specific approval of the British public. 'Never again', the new Tory campaigning slogan on the post-Lisbon EU, is "something every Conservative candidate can say on the doorstep". Even Ken Clarke approves the policy, he insisted. (William Hague, Liam Fox and George Osborne bothered to turn up for the speech, but Clarke was conspicuously absent.) Yet any future government could reverse the move through amending legislation. Cameron might want the convention to become part of the "furniture", but there are no real teeth here.

The same can be said of criminal justice, an area where the Tory leader was thoroughly uneasy. He avoided answering the question of whether or not the supreme court will remain - well - superior. The purpose of securing an additional protocol, Cameron explained, was to prevent the "legal and judicial drift" of the European courts into British law. It is not clear how this will be achieved.

Finally, and most bafflingly of all, comes the idea of a grand sovereignty bill safeguarding Britain's interests. It is fine-sounding. It will go far to placating those within the Conservative party who have moaned about the steady encroachment of European powers over the years.

It is also virtually meaningless. Cameron appeared to admit himself the idea would not have any practical bearing on Britain's relationship with the European Union as it stands at present. It exists as an "assurance" that Britain has the "final word on our laws". Germany is Cameron's role model - hardly the epitome of a eurosceptic state. Quietly persuading Tories sympathetic to Europe the proposal will not have any substantial meaning should be easy enough.

There are other measures to be considered, of course, which will leave European leaders feeling distinctly queasy. Renegotiating an opt-out from the Charter of Fundamental Rights and clawing back control over social and employment legislation will keep the diplomats busy. But the political impact of this policy - which will be stuck with until the end of the next parliament - lies in its clever use of rhetoric, its tactically brilliant deployment of symbolism. By fudging his policy on Europe, Cameron has ensured he will not be dragged down by its potential for division.

This is one of Cameron's most astute moments as party leader. He has once again shown masterful leadership of the Conservative party. That he has been forced to deploy policies which are little more than hot air is, when it comes to party unity, neither here nor there.