'Rab' Butler who has become Under-Secretary of State for Foreign Affairs... Butler is a scholarly dry-stick but an extremely able, cautious, canny man, of great ambition. I must cultivate him.

Rab (Butler) arrived, looking ridiculously like a Minister, at 7.10 a.m. I met him at the station and rather sleepily escorted him to the hotel. He was a touch aloof, as always when contact has been broken, and his clothes are really tragic. But he has a quiet, strong shyness which is deceiving.

We went to the League building, which is a vast affair, a huge modern, white, dignified, lavish, empty palace, as befits the meeting place of 47 nations. 47 nations in theory, but in reality, the League is now really only an anti-dictator Club. The bars and lobbies of the League's building are full of Russians and Jews who intrigue with and dominate the press, and spend their time spreading rumours of approaching war, but I don't believe them, not with Neville (Chamberlain) at the helm. He will wriggle out somehow.

We all dined gaily again tonight at the Plat d'Argent, and Rab almost embarrassed us once or twice with his high staccato laugh which, when he is amused, becomes veritably soprano, like a pheasant's call. But he charmed, and was charmed by, Diana (Cooper).

Tomorrow the League racket begins.

After the fiasco of Suez it was clear that Anthony Eden could not remain as Prime Minister. He fell ill during the crisis and resigned in January 1957. There was much speculation in the circles in which I moved as to who would succeed - in those days, of course, Conservative Leaders 'emerged' rather than being elected. My Conservative friends in Chambers were convinced that Rab Butler would never be summoned by the Queen because he was too left wing. By contrast, the Chancellor of the Exchequer at the time of Suez, Harold Macmillan, was considered to be the right-wing candidate. All of which shows how little we knew of the past and present convictions of both men - particularly the brilliant, elusive figure who was shortly to become Prime Minister.

Harold Macmillan had the strengths and weaknesses of the consummate politician. He cultivated a languorous and almost antediluvian style which was not - and was not intended to be - sufficiently convincing to conceal the shrewdness behind it. He was a man of masks. It was impossible to tell, for instance, that behind the cynical Edwardian facade was one of the most deeply religious souls in politics.

Harold Macmillan's great and lasting achievement was to repair the relationship with the United States. This was the essential condition for Britain to restore her reputation and standing. Unfortunately, he was unable to repair the damage inflicted by Suez on the morale of the British political class - a veritable 'Suez syndrome'. They went from believing that Britain could do anything to an almost neurotic belief that Britain could do nothing. This was always a grotesque exaggeration. At that time we were a middle-ranking diplomatic power after America and the Soviet Union, a nuclear power, a leading member of NATO, a permanent member of the UN Security Council and the centre of a great Commonwealth.

The Tories should have elected Rab Butler to succeed him. I expected them to do so and I would have enjoyed renewing the contest of the 1950s. But Rab did not have enough of the killer instinct to take over and his colleagues knew it. Instead, they chose the Earl of Home, who demoted himself to the House of Commons for the purpose. Politically I was pleased. Instead of the formidable Macmillan, with his deep knowledge of politics and administration, I was getting an opponent with very little experience of Parliament and much ignorance of economics.

He was to prove much more formidable than I expected. When the election came we only just scraped in and I am often asked whether we might have lost if Macmillan had been restored to power. It is very hard to say, but I doubt it. Macmillan had provided us with so much ammunition that I consider that we would have made mincemeat of him, whereas with Alec Douglas-Home our barrage was perhaps more subdued.

When the Tories were defeated in 1945 he (Rab Butler) was set to work in the research department of the Central Office of the Conservative Party, and he can be regarded as the architect of the policies which helped to produce victory in 1951.I was flattered to be told that Butler had carefully examined what I had done for the Labour Party prior to and during the 1945 election and told his staff that he wanted to do for the Conservative Party 'what Herbert Morrison had done for Labour'.

He had certainly learned the lessons of the 1945 defeat. The pamphlets he inspired indicated this. In 1945 the Tories had fought on a negative line of prophesying ruin under socialism and denouncing all the types of control that war had created. Churchill's 'Gestapo' reference in the 1945 campaign, though attacked by his own side after defeat, was in fact completely in line with the general Tory campaigns of that and previous elections and should have caused neither surprise nor consternation among his colleagues.

I can pay Butler the compliment of saying that his policy made Labour's fight more difficult. His more progressive attitude softened the contrasts of black and white; conflicts of principle diminished. And that was not good.

Yet Butler's methods were something of a pose. He is by nature conservative. As Chancellor of the Exchequer in 1951 he was reactionary. Some M.P.s question whether he has the style or the appearance of a Party leader, but he is not unprogressive in outlook on a number of subjects, and he has brains. He is a good Leader of the House, though a little over-afraid of it at times.

I knew that Rab was waiting in the Privy Council Chamber, a splendid room with high windows looking on to Horse Guards Parade. There I found him sitting at the table, deep in thought. Unusually for him, for he was a prodigious worker, he had no papers or folders in front of him. He was just patiently waiting for the news. As I entered, his face lit up with its familiar, charming smile. Every newspaper that morning, save one, had announced that he would be the new Prime Minister. All but one were wrong. I had a sad mission to carry out, but there was nothing I could do to soften the blow. 'I am sorry, Rab,' I said, 'it's Harold.' He looked utterly dumbfounded.

After a pause, I explained that the Queen had sent for Harold to go to the Palace after lunch. There was nothing Rab could say. I said again how sorry I was, adding that, perhaps, he would like a little quiet to himself before the announcement was made. Still he said nothing, and I left him, once again alone, in that large, grand room where so many matters of state had been decided over the centuries. I realised later that this had been a shock from which he never fully recovered and to which he never really adjusted his life or his personality. On many occasions in later years as we strolled around the grounds of his home in the country, or talked in his beautiful house in Smith Square with its glorious collection of Impressionists, he would suddenly ask me, 'Why do you really think that they did not want me to become leader of the party?' When a second opportunity for Rab arose on the resignation of Harold Macmillan six years later, he was still asking himself the unsolved question why it had not worked out for him last time around.

I had a lot of time for R. A. Butler. He seems to me to be a man who, in a way, destroyed himself, at least in a political sense. I suspect that he is enjoying himself more in academic life than he ever enjoyed Parliament. In politics he wasn't sufficiently dedicated to what he had to do. He was always too apologetic, too given to explaining himself. Yet I think he could have made a very considerable Prime Minister - I can't think that under him the country would have taken a single decision that was morally wrong. He is a pleasant man and a very good man - I mean a really good man. But he is not ruthless. He simply did not have what it takes to become Prime Minister.