When in May 1940 a tired, unpopular Neville Chamberlain resigned as Prime Minister there were two candidates for the post: Winston Churchill and Lord Halifax. The King knew that a large section of the Conservative Party distrusted Churchill and admired Halifax. Its views were conveyed to him in plain language.
According to The Gathering Storm, the first volume of Sir Winston Churchill's The Second World War, Lord Halifax told both Churchill and Chamberlain that his position as a peer outside the House of Commons would make it difficult for him to discharge the duties of Prime Minister. Ultimately a National Government including representatives of the Labor and Liberal parties was formed, but, according to Churchill, the King made no stipulation "about the Government being National in character."
Lord Halifax certainly doubted his ability to discharge his duties as Prime Minister. But apparently the question of whether he could form a National Government did not arise. In any event, the King, fully cognizant of the views of a considerable section of the Conservative Party on the relative merits of the two men and aware that it would have been possible to form a Conservative government under Halifax, sent for Churchill instead of Halifax and asked him to form a government. History may record this as a signal example of the remaining powers of the Crown.
Sir William Anson explained in The Law and Custom in the Constitution that the real power of the sovereign "is not to be estimated by his legal or his actual powers as the executive of the State.
"The King or Queen for the time being is not a mere piece of mechanism, but a human being carefully trained under circumstances which afford exceptional chances of learning the business of politics."
The monarch is not isolated from great affairs. The Queen sees from the inside the workings of government, knows the individuals concerned, and often has a surer sense of what the people will or will not accept than some politicians. So, Sir William reasoned, the sovereign in the course of a long reign may through experience become a person whose political opinions, even if not enforceable, will carry weight. Continuity in office, wide experience in contact with successive governments, and, finally, the influence that the monarchy exercises through an ancient and well-established tie with the people can confer upon the sovereign an influence far greater than is generally realized.
Queen Elizabeth II has twice used the royal prerogative of choosing a Prime Minister. On April 6, 1955, she chose Sir Anthony Eden to succeed Sir Winston Churchill. On January 10, 1957, she chose Harold Macmillan to succeed Sir Anthony. The second selection occasioned sharp political outcry. The "shadow cabinet" or Parliamentary Committee of the Labor Party, meeting in secrecy and dudgeon, reported that the Queen's choice had raised serious questions of a constitutional nature. It argued that the Conservative Party, by asking the sovereign to choose between Mr. Macmillan and R.A. Butler, had involved the Queen in partisan politics. The Tories, Labor said with a touch of self-righteousness, should always have a leader and a deputy leader of the party ready to assume the highest office when called.
(This raised the contingency, pleasing to Tories at least, of James Griffiths, the present deputy leader, as Prime Minister instead of Aneurin Bevan in the event of some serious accident to Hugh Gaitskell.)
The Socialists' argument that the Queen was forced to choose between Mr. Macmillan and Mr. Butler reflected a certain ignorance of what had been going on within the Conservative Party. It was apparent on the night of Sir Anthony Eden's resignation that Mr. Butler did not command the support of a majority of the Tory Members of the House of Commons. It was also apparent, or should have been apparent, that the Queen would be advised by the retiring Prime Minister, Sir Anthony Eden, and the two foremost figures in the party, Sir Winston Churchill and the Marquess of Salisbury. Anyone aware of the currents within the Conservative leadership during the last three months of 1956 could not possibly have thought that any one of these three would advise the Queen to choose Mr. Butler.
There was a good deal less to the high-minded Socialist protest than met the eye. The shadow cabinet made the tactical mistake of coupling the protest with a demand for a general election. One need not be cynical to emphasize the connection. But the spectacle of Mr. Bevan and his colleagues protesting like courtiers over the Queen's involvement in politics and quoting an editorial in The Times as though it were Holy Writ added to the gaiety of the nation.