The outcome of the seat switched permanently to electing the Labour candidate, in 1923 — save for the four-year term when the party's number of MPs fell from 327 to 52 seats (1931-1935) and when the seat elected notable women's right advocate Mrs Mavis Tate.
The 1918 legislation created a new parliamentary borough of Willesden, identical in area with the urban district of Willesden, and divided it into two single-member divisions. Willesden West comprised five of the eleven wards of the urban district: Church End, Harlesden, Roundwood, Stonebridge and Willesden Green. The remaining six wards formed the Willseden East division. In 1933 Willesden was incorporated as a municipal borough, although this made no change to the parliamentary divisions.[1]
When constituencies were redrawn prior to the 1950 general election, Willesden West was redefined in terms of seven wards of the borough as they then existed: Church End, Harlesden, Kensal Rise, Manor, Roundwood, Stonebridge and Willesden Green. Kensal Rise had previously formed part of Willesden East.[1]
Another General Election was required to take place before the end of 1940. The political parties had been making preparations for an election to take place and by the Autumn of 1939, the following candidates had been selected;
^ abcYoungs, Frederic A Jr. (1979). Guide to the Local Administrative Units of England, Vol.I: Southern England. London: Royal Historical Society. pp. 745–748. ISBN0-901050-67-9.