So what do you do, Mr Major?

As John Major resumes normal life at No 10, Peter Hennessy helpfully shows how the function of premiership has changed since the 1940s.

This is a very odd moment to be discussing the power of the premier. The weakness of the prime minister would seem a more appropriate topic. British politics has shown yet again just how vulnerable the possessor of the state machine can be.

In fact the power of the premiership rests on three interlocking circles. Leadership of the largest single party (usually) triggers command of the Commons which in turn propels you into temporary ownership of the executive. If either of the first two slip from your grasp, you are ejected from the third circle in a manner that can be very swift, as Mrs Thatcher found in November 1990.

None of the debates about what some scholars have even seen as the development of a "British presidency" have altered these essential facts of constitutional life. It is all about strength within weakness and weakness within strength and has been seen as such by the scholarly community for more than a generation, ever since Harold Macmillan appointed Lord Home as his foreign secretary during the 1960 reshuffle (and even more so since July 1962 when Macmillan sacked a third of his Cabinet).

The 1960 example of Downing Street patronage stimulated a correspondence in The Daily Telegraph, embracing Bob Boothby and Clem Attlee among others, about the alleged usurpation of traditional Cabinet government by a more prime ministerial variety. Scholar politicians, notably John Mackintosh and Dick Crossman, took up the theme and the debate has rumbled on in the exam papers ever since, roaring back into renewed life during the "command" premiership of Mrs Thatcher.

But much of the argument has been crude and imprecise, conducted, as Anthony King has put it, "at the level of a bar-room brawl", with competitive anecdote substituting for the traditional chairs and bottles of a pub fight. Definition has been lacking partly because of the fluid nature of procedures and relationships where politics and administration meet at their central government apex.

Stimulated by a remark of Sir Robin Butler's (the Cabinet Secretary told me in 1990 he would consult "the cupboards" before offering advice on the monarch's options in the event of a hung Parliament) I have been trying a different approach of late. It involves raiding the files of the Public Record Office to see what the guardians of our unwritten constitution thought it was at any given moment in the postwar period, in the hope of discovering the contents of those influential cupboards.

The yield has been thin apart from a single file on the "Function of the Prime Minister and his staff" which was placed in the still secret "Precedent Book" (which is kept in Sir Robin's office) in 1949. It assigned Mr Attlee the functions shown in Table One.

Had I (though less than three months old when the file began to do the rounds in Whitehall in 1947) been invited in to help, I would have added the following to those late 1940s functions: 1. Special responsibility for the secret services.

2. The making of nuclear weapons policy.

3. Managing relations with Opposition leaders.

4. Preparing the "War Book" in case the country found itself engaged in serious hostilities.

5. Responsibility for the overall load on government, and Whitehall efficiency generally.

6. Managing the "special relationship" with the US as part of the heads of government section.

7. Managing changes in the UK's constitutional relationship with the Empire and/or its former members.

To the best of my knowledge, no modern equivalent of that 1949 document exists in the Cabinet Secretary's cupboard. If one did, what would it look like? I have had a stab at creating a mock-up. Between Attlee and Major those duties have increased in a fashion that would have left Peel, Gladstone, Salisbury, Balfour, Asquith and even the highly prime ministerial Lloyd George breathless (see Table Two).

The 33 prime ministerial functions of 1995 do create the possibility of an over-mighty premiership. Between them they make a powerful case for collective restraint inside No.10 - ie, a vital and vibrant form of Cabinet government.

As this is the age of the Citizen's Charter what performance indicators should we apply to the full Cabinet before they can award themselves a charter mark? (see Table Three). Just after the 1992 election, Mr Major's Policy Unit suggested the Cabinet should be subject to a regime of performance related pay. "Oh no," the cry went up. "We can't have that. You can't measure what we do." I offer them the above criteria sans fee. After all, I am only here to help whoever is leading the Conservative Party or occupying No 10 this week.

Peter Hennessy is professor of contemporary history at Queen Mary and Westfield College, London.

Table one

FUNCTIONS OF THEPRIME MINISTER, 1949

1 Managing the relationship betweenthe monarch and the government.

2 Hiring and firing ministers.

3 Chairing the Cabinet and its most important committees.

4 Arranging other "Cabinet business", ie the chairmanships of other committees, their membership and agendas.

5 Overall control of the Civil Service as First Lord of the Treasury.

6 The allocation of functions between departments; their creation and abolition.

7 Relationships with other heads of governments.

8 A specially close involvement in foreign policy and defence matters.

9 Top Civil Service appointments.

10 Top appointments to many institutions of "a national character".

11 Certain scholastical and ecclesiastical appointments.

12 The handling of "precedent and procedure".

Table two

FUNCTIONS OF THEPRIME MINISTER,1995 CONSTITUTIONALAND PROCEDURAL 1 Managing the relationship between Government and monarch.

2 Managing the relationship between the Government and the Opposition on a Privy Counsellor basis.

3 Establishing the order of precedence in Cabinet.

4 Interpretation and content of procedural guidelines both for ministers and civil servants (including the final say in whether they should appear before parliamentary committees).

5 Changes to Civil Service recruitment practices.

6 Classification levels and secrecy procedures for official information.

7 Requesting the sovereign to grant a dissolution of Parliament.

APPOINTMENTS

(When I say "appointments" I mean the recommendation of an appointment to HM Queen, in whose name all thesethings are done) 1 Appointment and dismissal of ministers (final approval of their parliamentary private secretaries and special advisers).

2 Top appointments to the headships of the intelligence and security services.

3 Top appointments to the home Civil Service and, in collaboration (with the foreign secretary) to the diplomatic service plus (with the defence secretary) to the armed forces.

4 Top ecclesiastical appointments plus a handful of regius professorships and the mastership of Trinity College, Cambridge.

5 Top public sector appointments and top appointments to royal commissions and committees of inquiry.

6 The award of peerages and honours (except for those in the gift of the sovereign).

CONDUCT OF CABINETAND PARLIAMENTARY BUSINESS

1 Calling meetings of cabinet and its committees. Fixing their agenda.

2 The calling of "political Cabinets" with no officials present.

3 Deciding issues where Cabinet or Cabinet committees are unable to agree.

4 Granting ministers permission to miss Cabinet meetings or to leave the country.

5 Ultimate responsibility (with the Leaders of the Houses) for the government's legislative programme and the use of government time in the chambers of both Houses.

6 Answering questions twice a week (when the Commons is sitting) on nearly the whole range of government activities.

ORGANISATIONAL AND EFFICIENCY QUESTIONS

1 Organisation and staffing of No 10 and the Cabinet Office.

2 Size of Cabinet; workload on ministers and the Civil Service; the overall efficiency of government.

3 The overall efficiency of the secret services, their operations and their oversight.

4 The creation, abolition and merger of government departments and executive agencies.

5 Preparation of the "War Book".

6 Contingency planning on the civil side (with the home secretary) eg for industrial action that threatens essential services or for counter terrorism.

7 Overall efficiency of the government's media strategy.

BUDGET AND MARKET SENSITIVE ECONOMIC DECISIONS

1 Determining, with the Chancellor of the Exchequer, the detailed contents of the budget. By tradition, the full Cabinet is only apprised of the full contents of the budget statement the morning before it is delivered. But since the inauguration of the "combined budget" in November 1993, a Cabinet committee shapes the content of the public expenditure component of the Budget ahead of its final compilation.

2 Determining which ministers (in addition to the Chancellor) will be involved, and in what form, in the taking of especially market sensitive economic decisions such as the level of interest rates.

SPECIAL FOREIGN AND DEFENCE FUNCTIONS

1 Relationships with heads of government (eg the nuclear and intelligence aspects of the US/UK "special relationship").

2 Representing the UK at "summits" of all kinds.

3 With the defence secretary,the use of the royal prerogative to deploy Her Majesty'sforces in action.

4 With the foreign secretary, the use of the royal prerogative to sign or annul treaties, recognise or derecognise countries.

5 The launching of a UK nuclear strike. (With elaborateand highly secret fall-back arrangements in place in case the PM and the Cabinet were wiped out by a bolt-from-the-blue in a pre-emptivestrike - the so-called "Decapitation" scenario orthe "Headless Chickens" scenario, depending uponthe level of comedienoire prevailing inWhitehall).

Table three

THE PURPOSES OFCABINET GOVERNMENT.

1 The Cabinet is the ultimate arbiter of all government policy.

2 Cabinet and Cabinet committee business consists chiefly of questions which significantly engage the collective responsibility of government because they raise major issues of policy or because they are of critical importance to the public or matters on which there remains disagreement between government departments.

3 Cabinet must act as a necessary restraint upon a potentially over-mighty premiership.

4 It must bring wider political considerations to bear on technical and administrative matters (this is especially important on big, science-related procurements or when a "war cabinet' is in operation).

5 It must blend as genuinely and effectively as possible the width of opinion represented by the coalitions of views which make up Britain's two main parties in such a way that outcomes can be accepted by the Cabinet as a whole.

6 It must strive to treat issues in the round with secretaries of state being capable of raising their eyes above their narrow ministerial concerns in what Gladstone once called a "Government of Departments".

7 It must ensure that the decencies, probities and accountabilities of British public and political life are maintained in relation to: a. Parliament.

b. The public in its dealings with government departments and agencies.

c. The raising and disbursement of public money.

d. The non-partisan deployment of the apolitical Civil Service.