Some members of the Labour Party disapproved of the electoral truce between the main political parties during the Second World War and on 26th July 1941 members of the 1941 Committee led by Richard Acland, Vernon Bartlett and J. B. Priestley established the socialist Common Wealth Party. The party advocated the three principles of Common Ownership, Vital Democracy and Morality in Politics. The party favoured public ownership of land and Acland gave away his Devon family estate of 19,000 acres (8,097 hectares) to the National Trust.
Kitty Bowler was on the National Committee of the Common Wealth Party (CWP) and during this period came into conflict with Richard Acland. He accused her of having a "more chaotically disorderly brain than anyone I've ever met... you are wholly incapable of holding an organised part in any discussion or argument." Kitty replied that the CWP "is disintegrating because of attempts to turn it into an autocratic pseudo-religious body with fascist tendencies."
In 1942 the Common Wealth Party decided to contest by-elections against Conservative candidates. The CWP needed the support of traditional Labour supporters. Tom Wintringham wrote in September 1942: "The Labour Party, the Trade Unions and the Co-operatives represent the worker's movement, which historically has been, and is now, in all countries the basic force for human freedom... and we count on our allies within the Labour Party who want a more inspiring leadership to support us." Large numbers of working people did support the SWP and this led to victories for Richard Acland in Barnstaple and Vernon Bartlett in Bridgwater. Later, Victor Gollancz argued that "had there been no Left Book Club there would have been no Bridgwater."
Tom Wintringham decided to stand for the CWP in the safe Conservative seat of North Midlothian. People who campaigned for him included H. G. Wells, J. B. Priestley, H. N. Brailsford, Sybil Thorndike, Naomi Mitchison and Kitty Bowler. The by-election took place on 5th February 1943 and Wintringham won 48% of the vote but lost to the Solicitor General for Scotland, Sir David King Murray by 869 votes.
Over the next two years the CWP also had victories in Eddisbury (John Loverseed), Skipton (Hugh Lawson) and Chelmsford (Ernest Millington). George Orwell wrote: "I think this movement should be watched with attention. It might develop into the new Socialist party we have all been hoping for, or into something very sinister." Orwell, like Kitty Bowler, believed that Richard Acland had the potential to become a fascist leader.
Negotiations went on between the CWP and the Labour Party about the 1945 General Election. Richard Acland demanded the right to contest 43 selected Conservative-held seats without opposition from Labour in return for not contesting all other constituencies. After this offer was rejected, Tom Wintringham met with Herbert Morrison, and suggested this be lowered to "twenty middle-class Tory seats". Morrison made it clear that his party was unwilling to agree to any proposal that involved Labour candidates standing-down.
Tom Wintringham was commissioned by Victor Gollancz to write a book, Your MP. The book sold over 200,000 copies and was a best-seller during the 1945 general election campaign. The book contained an appendix detailing how 310 Conservative MPs voted in eight key debates between 1935 and 1943. However, this book seemed to help the Labour Party as they ended up with 393 seats, whereas only one of the CWP twenty-three candidates was successful - Ernest Millington at Chelmsford, where there was no Labour contestant.
The Common Wealth Party was dissolved in 1945.
In July 1942, the 1941 Committee merged with a band of Richard Acland's supporters known as Forward March to form a new political party under the name Common Wealth, and almost the only members of the committee who stayed on were Vernon Bartlett, Tom Wintringham and J. B. Priestley, who became chairman. Before autumn, both Priestley and Bartlett had resigned. Common Wealth never succeeded in its aim of becoming a mass movement, probably because under Acland's direction its drive was more towards encouraging moral revival than to attracting public support; but in the curious circumstances of the time-in which the main political parties, being in coalition, could not oppose each other at by-elections - it did succeed in winning three by-elections against Conservative candidates, giving it, including Acland himself, a total of four Common Wealth MPs.
Kirn Mackay comes, at his own request, to propose the affiliation of Common Wealth to the Labour Party, and to ask whether I thought such a suggestion would be accepted. I said that there would be some opposition, since we are rather against affiliating odds and ends, and it might be felt that it would be more difficult to refuse the Communists if we had already accepted Common Wealth. I said a simpler plan, to which no effective objection could be taken, would be to dissolve Common Wealth and tell all its members to join the Labour Party. (This, I said, was what I had proposed to Maisky once about the British Communists, and he had said it was "an interesting and novel idea" and he would report it to Moscow. Though nothing more had happened about it.) Mackay said that this would indeed be more logical, but that he was not sure whether all their members, many of whom, he said, were very useful and intelligent middle-class people, and their regional organisers, of whom there were seventeen or eighteen, would follow such a lead. But he was very humble and non-aggressive and obviously felt that he had nothing much to offer. They would not, he said, want to have any separate programme of their own. They would never run a candidate against a Labour candidate (Acland had at once withdrawn from Waterloo when we adopted a Labour candidate, though there had been none in the field when he went there), they had been taking an interest in 180 constituencies, where either there was no Labour candidate or where they felt that they had a better chance of winning than we had.