I wish Mr Hamilton the best of legal luck

The Court of Appeal is shortly to deliver a judgment of constitutional importance. It is about whether Mr Neil Hamilton can sue Mr Mohamed Al Fayed for libel. In one form or another, the case has been going on for some years now. It is not yet on a par with Jarndyce v Jarndyce in Bleak House but is proceeding in that direction.

The latest twist is that Madam Speaker Boothroyd has involved herself on behalf of the House of Commons - and on the same side as Mr Fayed. She is represented by Mr Ross Cranston, the Solicitor-General, who normally appears for the Government. He did not appear in the High Court last summer, when Mr Justice Popplewell decided that Mr Hamilton could go ahead and sue Mr Fayed. Nor did he appear before the Court of Appeal in November, when leave was given to Mr Fayed to appeal against Mr Justice Popplewell's decision. But he turned up in the higher court last week, arguing in the company of Mr George Carman (who appeared for Mr Fayed) that Mr Hamilton should not be allowed to go ahead.

I may have missed something - it has been known to happen - but I am unable to find any resolution of the House or other instruction to the Speaker authorising her to intervene through counsel on Mr Fayed's side. She seems to have acted of her own initiative and engaged the Solicitor to act for the House, which seems odd to me.

It is a tangled tale which goes back to article 9 of the Bill of Rights 1688. This says that "the freedom of speech and debates or proceedings in Parliament ought not to be impeached or questioned in any court or place out of Parliament". This is fairly clear, as these things go. It means that MPs can say what they like in the House without being at risk of being hauled before the courts in defamation or other proceedings. On balance this is probably a good thing, even though honourable members sometimes abuse the privilege, as Mr Brian Sedgemore did when he suggested that the editor of the Sunday Telegraph was a spy.

Not only is the language fairly clear. The original purpose was manifest as well. It was to protect Parliament against the Crown, against the King and his bullyboys. But this sensible - in the late-17th and early-18th centuries necessary - principle became, by a process of extension, muddled with another principle: that the House was the sole judge of its own proceedings.

Up to a point, again, this was sensible enough. A court cannot argue with an Act of Parliament: not only with what it says but with the way in which it was passed. Life would be impossible if litigants could return for a stroll round the division lobbies. But in the 19th and 20th centuries the courts carried this principle of internal parliamentary self-government, which was logically separate from that of freedom of speech, to absurd lengths.

Until a recent Lords case, for instance, it was impossible to quote Hansard in court without the most tremendous carry-on which involved seeking the gracious permission of the Speaker or some such flummery. Indeed, the cowed posture which the courts take towards Parliament was the principal cause of Mr John Major's troubles deriving from corruption in 1992-97 and of Mr Hamilton's consequential legal actions.

The confusion of which I speak did not mean that MPs were prohibited from taking actions for defamation themselves. Not a bit of it. We might not be able to sue them, but they could certainly sue us. Until the advent of Mr Rupert Allason as a litigant, the most successful plaintiff was Barbara Castle, followed by George Wigg, though she came a cropper in the so-called "torture in Cyprus" case.

In 1979 Lady Castle successfully sued the Daily Mail for casting aspersions on her division record. The case is interesting in the present context because it certainly involved "proceedings in Parliament". But the Mail made no attempt to have the case dismissed on the ground that mounting a successful defence would have involved such proceedings and accordingly, under the now fashionable foolish interpretation, contravened the Bill of Rights.

This was precisely the ground which the Guardian successfully pleaded when Mr Hamilton and the lobbyist Mr Ian Greer tried to sue it for saying they were corrupt. The judge accepted the paper's argument that it would not be able to cite parliamentary proceedings and would therefore be unable to conduct a proper defence. The case collapsed; though it may well have collapsed anyway for other reasons, not least a breach between Mr Hamilton and Mr Greer.

Nevertheless various Conservatives felt Mr Hamilton had been treated unfairly. Lord Hoffmann was prevailed upon to make an amendment to the Defamation Bill then going through Parliament. He is not a Conservative but a Lord of Appeal who cannot attach himself to any party. He might have been more prudent in this matter also to keep his head down. But he thought then that he was acting in a good cause.

The new section in the Defamation Act 1996 says that where the conduct of a person in relation to proceedings in Parliament is in issue in a defamation case, he may waive "the protection of any enactment or rule of law which prevents proceedings in Parliament being impeached or questioned in any court or place out of Parliament".

By implication, this accepts the erroneous interpretation of article 9 of the Bill of Rights. It assumes that the reasoning of the judge in the Guardian case was correct. It merely puts a plaintiff-MP such as Mr Hamilton in a better position than he occupied at that time.

Suppose it is Mr Fayed who is suing Mr Hamilton for libel, instead of the other way about. Mr Hamilton insists that Mr Fayed can make no reference to proceedings in Parliament in the conduct of his case. That would be the end of the matter. The case would collapse.

To this extent, it is a good thing that the Court of Appeal under the Master of the Rolls, Lord Woolf, is having another look at the question. The proper, the just answer is that plaintiffs and defendants alike should be able to refer freely to proceedings in Parliament irrespective of whether they are members or engaged in defamation proceedings. This is what scholars do in their books and journalists in their columns and no one takes any exception. The ancient confusion between freedom of speech in the House and the right of Parliament alone to regulate its own proceedings should at last be cleared away.

The trouble is that Mr Hamilton is trying to overturn the verdict of a committee under the then Parliamentary Commissioner for Standards, Sir Gordon Downey, which was endorsed by the House. The committee found that Mr Hamilton had accepted money in brown envelopes from Mr Fayed's employees. Mr Hamilton denies this and is seeking to overturn Sir Gordon's conclusions.

Neither a civil nor a criminal court, Sir Gordon and his colleagues operated under their own procedures. Mr Hamilton thinks an injustice was done to him. Helped by a voluntary fund, he hopes to demonstrate this by means of an action against Mr Fayed. He should be allowed to carry on suing, unimpeded by Madam Speaker, Mr Solicitor or anyone else.