In 1915, Hart joined the Workers International Union at Beardmore’s, the Dalmuir shipyard,
two years later he became a member of the Socialist Labour Party, the bulk of which was to enter the formation process that led to the Communist Party. In 1922, Finlay Hart was one of the founders of the Clydebank Communist Party.
From 1923 to 1926, he worked in Canada and was a member of the Communist Party there. Having returned to Britain, he resumed his membership of the British Party and became a long-term elected Communist Councillor for Clydebank until the 1960s, with the team of fellow Communist councillors, Arnold Henderson in the 5th ward and Jock Smith. (Arnold died at the end of 1980; he was a long standing AEU activist, and a regular at the Radnor Park bowling club, albeit a strict teetotaler. The Club still has an Arnold Henderson trophy awarded every year in one of their competitions.)
In 1932 Finlay Hart stood as a Communist candidate in Clydebank, Glasgow, Scotland with four other Communist party candidates; Robert Bird, Charles Hughes, James T Laird, George Hyslop. Their election address read: "We enter the election not with the cry of "save the Rates" but with the cry "Save the working Class" who are being systematically robbed and swindled. We say quite frankly in opposition to Moderate and Labour cries of Lower Rates that:- "We fight for higher rates and heavier taxes for the wealthy classes, We fight for lower rates for every working class area"
As convenor of the Blythswood shipyard, Finlay Hart played a prominent role in the Boilermakers Society. He was a member of the Central Committee of the Communist Party from 1935 to 1943. He became a full time worker for the Party in 1949, retiring in 1963, having been Scottish Secretary and National Industrial Organiser and a member of the EC and PC.
Hart was also a Communist county councillor for Dunbartonshire, Chair of the Scottish Party, and parliamentary candidate for the Springburn consituency.
In recognition of his three decades as a Communist councillor in Clydebank, Hart was honoured with the `provost-ship’, equivalent to mayoralty, of the borough in his later years in recognition of his long service.
Amongst his many pamphlets for the Communist Party were: `The Communist Party and the trade unions’ (1958) and `Shipbuilding - looking forward’ (1960). Finlay Hart died aged 88 in 1989.
Morning Star December 28th 1989 and other sources