Career
Educated to secondary school level, Lauchlan joined the Independent Labour Party in 1933, then in 1935 switched to the Communist Party of Great Britain (CPGB). He quickly rose to prominence, serving as Lanarkshire Organiser in the 1940s, then becoming Scottish District Secretary in about 1951, then in the 1960s served as National Organiser. He was also active on Glasgow Trades Council, and in 1946 represented it at the Scottish Trades Union Congress.
Lauchlan stood for the CPGB in Glasgow Govan at the 1950 United Kingdom general election, then in West Fife in 1951, 1955, 1959 and 1964, although he was never elected.