Alan Watkins: The longer the police investigations take, the more likely is Mr Blair to exit soon

In one of his immortal "Ukridge" stories, PG Wodehouse relates the arrest of his principal character at a by-election meeting. He is accused of stealing an expensive motor-car by a policeman who has forced his way on to the platform. It turns out that the vehicle in question had been borrowed by Ukridge from a friend to assist another friend in his parliamentary campaign. In the end, matters are cleared up, though not before several misunderstandings and a certain amount of political damage along the way.

Quite enough damage has already been brought about by the affair of loans (or it may be cash) in return for peerages. It remains to be seen precisely what turn the case will take. As I wrote last week, the authorities in No 10 and the commentators in the press, or most of them, have alike underestimated the seriousness of the whole business. Well, I told them, but they wouldn't listen.

Matters may still not be allowed to proceed beyond January, whether because there is a want of evidence that will stand up in court or because the prosecuting authorities (which may or may not include the government's own Attorney General), do not want to take the case any further. When you come down to it, both reasons amount to the same thing.

But the stream has gathered so much floodwater along its course to the sea - here a Lord Levy, there a Jonathan Powell, somewhere else a more obscure party apparatchik - that it cannot be allowed simply to trickle into the sands. Perhaps Lord Hutton could be called out of retirement to provide a suitably reassuring note. Or another senior judge, flanked by two scarcely less eminent lawyers, could be summoned to conduct an investigation under the Tribunals of Inquiry (Evidence) Act 1921.

This would take years. There would be champagne on tap in the Temple and complimentary port in the evening. Not only would Mr Gordon Brown have succeeded Mr Tony Blair, but there would have been a general election, with what consequences we cannot tell; the lawyers would still be gliding smoothly in and out of Church House, Westminster, or wherever it happened to be; while the newspapers would long ago have lost any interest in the proceedings which they might once have possessed.

Lord Falconer, the Minister for Constitutional Affairs, is an ingenious chap - it was he, after all, who first imported Lord Hutton into our public affairs - but even he would not have been capable of inventing a wheeze to bury the peerage question for the foreseeable future. Mr John Yates ("Yates of the Yard"), has interviewed 90 witnesses or thereabouts, or his colleagues have done so, or are about to do the same. As Home Secretaries used to say in the bad old days of hanging, the law must take its course.

From time to time, governments get themselves into trouble of one sort or another of a political-legal nature. This is one of those occasions. There are several well-tried techniques which the government - any government - may employ, whether singly, in combination or in the alternative, where defences, excuses or justifications may conflict with each other, as happens with accused persons in criminal trials all the time.

The most trusted technique, which I have already mentioned, is usually that of the tribunal or department inquiry. By the time the investigation is completed, everyone has forgotten what the row was about in the first place. Alas for the Falconers of this world, the criminal law has taken a hand at an early stage of the proceedings - at perhaps too early a stage. An inquiry is obviated, though one can never be sure of these things.

Another approach is for the government to claim that the matter at issue is "boring" or "too technical" or "remote from the concerns of ordinary people". Ministers have already had a stab at this approach, with a certain amount of success as far as party members are concerned, or those of them who choose to remain in the fold. Peerages, the composition of the House of Lords, even the question of party funding are alike remote from the preoccupations of those who toil in the party vineyard.

This is a continuation of the pathway that leads into the undergrowth of resentment. By a miraculous process of transmogrification - turning, so to speak, impure wine into the most crystalline water - so millionaires and seats in the House of Lords are transformed into the bone and sinew of the People's Party. Everyone is against the party: policemen in their stations, and television reporters with cameras, and superior leader-writers in the papers.

The latest person to be involved is Mr Brown. So far, the Chancellor has given a wide berth to these stirring events. To become Minister for the Interior as well as First Lord of the Treasury: that seems to be the limit of his ambitions for the time being. But a curious theory surfaced in a column in The Guardian last week. Unless I have misunderstood it, this was to the effect that the constabulary wanted to prolong the developments about the peerages, because to do so would be to keep Mr Blair in office for longer than most people expected, so putting off Mr Brown's succession yet again.

I am sorry, but I am unable to see this. On the contrary: the longer the investigation takes, the more likely it is that Mr Blair will have to leave No. 10 sooner rather than later.

What is true is that Mr Blair is more closely involved with the continuing investigation than Mr Brown is. Even so, they are both in this together. I have outlined the various techniques which governments have developed for extracting themselves from legal-political morasses. The most powerful technique of all is to employ the brute force of a parliamentary majority by means of a vote of confidence. This was precisely what Ramsay MacDonald proved unable to do after the Attorney General of his day withdrew a prosecution in 1924.

Last week I mixed up two Tory politicians of a former age, both of them involved with the Suez operation. I wrote that Lord Kilmuir, the Lord Chancellor, had sent a mxdemorandum to Anthony Eden, questioning the legality of the war. In fact, Kilmuir had given grudging support to Eden. The doubter was an even crustier Conservative, Sir Reginald Manningham-Buller, the Attorney General, who had written to the then Prime Minister to this effect.

It is his daughter, Dame Eliza, who now advises the present prime minister on security matters, and enables us to sleep safe in our beds; or so it is devoutly to be hoped. To judge from the contents of the Queen's Speech, Mr Blair has little else with which to occupy himself in the evening of his days at No 10.