John Major's harsh words about how his predecessor turned his government into a Greek tragedy have lifted the veil which hides the inner workings of government. They do, however, have to be put into context. Lady Thatcher has not just been an embittered politician lusting for office. Throughout the years she has had little interest in glory for its own sake. Unlike Churchill she has never been motivated by a yearning for fame and fortune. For her power was the necessary precondition for turning ideas and beliefs into policy and practice. I recall a Cabinet meeting when she described a proposal as radical and then added: "But that's what we're here for."

So from her perspective her criticisms of John Major, her constant interference and her unhelpful interventions have been motivated by a sense of public duty rather than for reasons of mischief or because of a vendetta. A charitable observer can accept that but still feel that Major has been entitled to feel fed-up to the back teeth with her behaviour.

Comparisons are made between her attitude to her successor and that of Ted Heath to her. There are some striking similarities. Heath and Thatcher have far more in common with each other than either would feel comfortable in admitting. Both are strong-willed, stubborn and convinced of their own rectitude. Both have seen the Tory party as a vehicle for delivering power rather than - as John Major does - a historic institution, deserving commitment and loyalty. Major is a more natural Tory and Conservative than either of them in his instincts, values and beliefs.

But although Heath and Thatcher make a somewhat unlikely odd couple Thatcher has much less justification than Heath in her attitude to her successor. Thatcher was directly responsible for Heath's expulsion from the party leadership. But for her decision to stand for the leadership Heath might have stayed in control and returned to Downing Street in 1979. She made that impossible.

No comparable accusation can be made against Major. He did not plot against her. He was her own choice as her preferred successor. The worst accusation that any Thatcherite has been able to throw at him was that he chose to have an operation on his wisdom tooth during the leadership struggle, thereby absenting himself from zealous support. That is pretty weak beer in the frothy history of political knavery.

In many ways Margaret Thatcher has been unfortunate. She was a mere stripling of 65 when she was driven from power never to return. She is still 10 years younger than Gladstone was when he formed his last administration, not to mention Churchill or Adenauer.

The truth of the matter is that if Major was a great disappointment to Thatcher she has only herself to blame. She made him Foreign Secretary and then Chancellor of the Exchequer on the flimsiest evidence that he was a natural Thatcherite. I was always puzzled by her early enthusiasm for him. His ability and political skill were never in doubt but he never seemed to me to be a right-wing Conservative in the mould of Norman Tebbit, Nicholas Ridley or John Redwood. He was tough on public expenditure control, the battle against inflation and on privatisation. But so was Kenneth Clarke and Geoffrey Howe. On Europe and on social policy he was always - dread word - a pragmatist, and he made little effort to hide it. Once in Cabinet Thatcher came out with some particularly reactionary comments on an aspect of housing policy. Major, who was sitting next to me, did not conceal his distaste for her remarks.

Mrs Thatcher must have been aware that John Major did not share all her views but in the immediate aftermath of her resignation her overriding preoccupation was to stop Michael Heseltine becoming Prime Minister. He, she believed, would destroy all she had achieved. With Major there was a reasonable prospect he would carry forward the flame.

In any event, she assumed, she would still be able to assert enormous influence. Hence, her notorious remark that she expected to continue in control as a backseat driver. That was not only an ominous statement for the new Prime Minister to hear. It also made inevitable from the very beginning his need to demonstrate his independence and be his own man. The only way he could do that was by distancing himself from her not only by a different style but by different policies and priorities.

It was not just Europe where Thatcher and Major differed. Margaret Thatcher for all her undoubted patriotism and national appeal was very partisan in her loyalties. In the Conservative Party she considered you were either "one of us" or outside the pale. On several occasions when social security, housing or education policy was being discussed she would accept that some proposal would be harmful to a particular section of the public but feel that that could be disregarded because they "were not our people". That was not so much a reference to the social class of the people concerned but to their presumed political loyalties. Ratepayers and property owners were not only more responsible people; they were also likely Tory voters. Major, like all politicians, did not ignore these considerations but he did accept the obligation to try and devise policies acceptable to the nation as a whole.

The differences between them on Europe were less fundamental than is often assumed. For his part, Major was no more a federalist believer in a United States of Europe than she was. Likewise, despite the rhetoric it was Thatcher who signed up for the single market which provided for the greatest ever extension of majority voting. Both realised that the protection of British interests sometimes required concessions and compromise but sometimes needed defiance.

There were, however, two differences that had huge consequences. The first was that Thatcher always had a healthy majority and was never in danger of defeat in the Commons. Even when the Teddy Taylors, the Teresa Gormans and the Bill Cashes voted against her on Europe, no one noticed because the only effect was to reduce the government's majority by 10. When the same "dirty dozen" voted against Major the government's majority was wiped out and the future of the government was at stake.

The second difference was the result of rhetoric and gut instincts. Major is a consensus politician who does not relish conflict though he can be as tough as old boots when he considers it necessary. For Margaret Thatcher, the only consensus she believes in is a consensus behind her convictions. Major saw compromise on Europe as the way that civilised nations resolve their differences. For Thatcher, any compromise had to be extracted like a bad tooth and was resented thereafter. The Eurosceptics, therefore, forgave her in a way they would never forgive John Major. This was a running sore during the Maastricht debates and made inevitable the atmosphere of a Greek tragedy to which John Major has referred.

I have not yet read John Major's memoirs, but I hope that they are robust. If he makes criticisms of former colleagues such as Lady Thatcher it is not because he is thin-skinned but because the only justification for such books is that they give an honest account of the tensions which exist within all governments but which an army of spin doctors are hired to try to conceal at the time. And, anyway, Margaret Thatcher did not pull any punches when she published her own memoirs, despite her former colleagues still being serving Cabinet ministers.

Now these tempestuous years are behind us and we can only sit and admire the tranquil and loving relationship between Tony Blair and John Prescott as they lead a united and loyal Cabinet anxious only to serve the national interest. Sic transit ....

Sir Malcolm Rifkind served in the cabinets of both Margaret Thatcher and John Major and was foreign secretary in the last Conservative government.