Alan Watkins: There's only one way to keep Mr Blair in his place ...

Long ago, when Winston Churchill was coming to the end of his last administration, he was visited by the chairman of the 1922 Committee, Sir Derek Walker-Smith. The purpose of the visit was to discuss the government's proposal to increase judges' salaries, to which the backbenchers were opposed. Churchill explained peremptorily that this was government policy and would duly be put before the House of Commons.

"In that case, sir," Walker-Smith said, "I am bound to tell you that we shall vote against."

"Young man,'' Churchill replied (Walker-Smith was in his mid-forties), "that puts an entirely different complexion upon the matter."

The government did not proceed with its measure. This account was confirmed to me by Lord Broxbourne (as Walker-Smith had become) not long before he died.

The Conservatives then had a majority of 19. Government defeats in the House were not so common then as they were to become. They were possible all the same. The most famous was one on tied cottages. Churchill was clearly concerned to avoid another defeat.

Last week the detailed or, rather, undetailed proposals of the Queen's Speech were overborne by lamentation about the low turnout, which gave Mr Tony Blair a majority of 167 on a vote of slightly less than 25 per cent of the electorate. The phrase "democratic deficit'', previously used about the European Union, was heard. There was talk of the need for Parliament to hold the Executive to account. The Hansard Society published a praiseworthy report on the subject.

The subject is more complicated than it used to be because it is not at all clear what the Executive now comprehends. In the old days it used to consist of ministers and civil servants. But in the last 30 years, the report says, formerly ministerial functions have been assumed by agencies of one sort or another. I should have put it at 20 years myself. The greatest supporter of the public corporation since Herbert Morrison was Margaret Thatcher. There are bodies which did not exist even 10 years ago.

Is Railtrack, for example, part of the Executive? It is a state-created body whose principal function it is to take money supplied by the Government away from the taxpayer and to distribute it among its shareholders. Similar illustrations could be multiplied. Not only can Parliament not control these bodies. The ministry which is closest to them – often there are two or three competitors – cannot control them either. It is a pity that the old Select Committee on Nationalised Industries, instead of being abolished, did not have its functions extended to cover all these new agencies.

The Hansard Society places most of its faith in the departmental committees which were set up in 1979, supplanting the old specialist committees (such as the nationalised industries committee). A few of the old committees were allowed to remain, notably the recast Committee of Privileges and the Public Accounts Committee on which Mr David Davis made his name. But the theory was that ministers would be held more closely to account by committees which supervised government departments rather than more or less defined areas. The creator of these new committees was Norman St John-Stevas as Leader of the House, now Lord St John of Fawsley. He did this in the face of the opposition of Lady Thatcher and the indifference or hostility of most of his cabinet colleagues. He deserves the highest credit as an innovator.

If the committees have not been a complete failure, as they have not, they have hardly been an unqualified success either. It is not so much that they can be made to look foolish by witnesses such as Mr Kelvin MacKenzie, which was wholly to be welcomed, or by the Maxwell brothers, who remained more questionably silent under the protection of George Carman. It is, rather, that their composition and, often, their subject of inquiry are under the control of the government Whips. The removal of the troublesome Ms Diane Abbott from the Treasury Committee was a scandal.

The remedy lies with the committee chairmen – and with the House itself. In the 1970s, for instance, Harold Wilson prohibited Harold Lever from appearing before a committee to talk about the Chrysler company. The committee could still have summoned Wilson, Lever or both to put in an appearance and, had they refused, reported them to the House, which could in turn have reported them to the Committee of Privileges. But nothing of the sort happened. Few with any experience of Westminster would have expected it to happen. It is a place where what is thought to be the balance of party advantage overrides all other calculations.

It is for this reason that I think the Hansard Society's hope that a new race of committee-sitters will rise up is unlikely to be fulfilled. Certainly Mr Chris Mullin has relinquished a small post in government ("Minister for Late-night Debates" was what he called himself) to return to being chairman of a committee. There have always been respected committeemen in the House such as Mr Robert Sheldon, who retired at the election. Most MPs would still prefer to make their careers either as members of the diminishing band of independent backbenchers on the floor of the House or, the majority of them, as ministers ending up in the Cabinet.

In these proposals for the strengthening of committees there is a certain element of fraud on the backbencher. It has happened before. In 1966 Labour was returned with a majority of 96. The new Leader of the House was R H S Crossman, an even cleverer man than his successor Mr Robin Cook. Crossman was concerned that his charges would not have enough to occupy themselves with and would get into mischief. Accordingly he proposed that they take an interest in the House's committees.

Alas – or happily – the new MPs proved largely immune to his blandishments: partly, no doubt, because they were disinclined to make the effort which service on a committee entailed, as it still does, but partly also because they saw through Crossman's ploy of finding work for idle hands. Instead they preferred to make trouble for the government, whether over its prices and incomes policy, now lost in the vaults of Whitehall, or over its support for the United States in Vietnam. Indeed, one member of the Tribune Group, Russell Kerr, was employed as the group's Whip to calculate how many of his colleagues could safely abstain or vote against the government without endangering its survival. Rebellion, with its concomitant popularity in the constituencies, was rationed.

With its even larger majority, this government has no need for such a figure. The equivalents of Vietnam and incomes policy are, respectively, Mr George W. Bush's missile-defence plan and Mr Blair's proposals for part-privatisation in health and education. As Churchill recognised in 1954, there is no more effective control of the Executive than a threat to vote against it.