IT is a strange day indeed when the Deputy Prime Minister is unable to take his seat in the House of Commons because he feels he might be a "distraction".

The absence of the Liberal Democrat leader, Nick Clegg, absence from yesterday's statement on the European Union summit by the Prime Minister, David Cameron, was not only a sign of political and personal weakness on his part, it was also an insult to Parliament and the country. He is part of the Government led by David Cameron and on an issue as vital to Britain's national interests as Europe, it was surely his duty at least to turn up.

His no-show was presumably intended as a mute rebuke to the Prime Minister for "giving up Britain's seat at the EU top table", as one Liberal Democrat MP put it. But in doing the same thing to Parliament he has only underlined how marginal is the Liberal Democrat influence in the Coalition he formed with David Cameron only 18 months ago.

Of course, we feel his pain. For many Liberal Democrats, and in particular for Mr Clegg, Europe is the nearest thing they have to a religion. The idea that they are now hitched to a Conservative-led coalition that appears to be taking Britain out of Europe really hurts.

But surely if he wanted to demonstrate his determination to prevent that breach with Europe, he ought to have been present in the chamber where these matters are ultimately resolved. For, if Mr Clegg is guilty of weakness, Mr Cameron is guilty of self-delusion. Basking in the adulation of his eurosceptic backbenchers, the Prime Minister said he made "no apology" for refusing to accept a treaty that placed the City of London at risk of further regulation from Europe.

But in what way has that risk been reduced by his use of the veto? The EU Commission vice president with responsibility for financial affairs, Olli Rehn, has made clear that Britain will be subject to the reforms to financial services whether Mr Cameron accepts them or not. The 26 other members will carry on with their "fiscal compact" to deal with the euro crisis without Britain having any say on its final shape.

All that Mr Cameron has achieved is the isolation of Britain from decision-making process on matters of vital economic interest to Britain. This was not a triumph but a diplomatic failure, as the SNP leader, Alex Salmond, was quick to point out yesterday while demanding to know why the PM had not consulted on the implications for Scotland.

Mr Salmond can be accused of opportunism given his failure to clarify his own party's attitude to euro membership. However, as the former Liberal Democrat leader, Lord Ashdown has said, Mr Cameron's "empty chair" policy in the EU cannot but strengthen the Nationalist case for Scotland having its own representation at the top table of Europe. After all, who are the separatists now?