Born in St Helens, then in Lancashire, Forshaw worked underground as a coal miner before working above ground on the mining machinery.
[1] He was a founder member of the Labour Representation Committee, and he was elected to St Helens Borough Council in 1905, remaining on it for many years.
[2][3] From 1908 to 1913, he was the political agent for the Labour Party in the Newton constituency.
[1] Forshaw was active in the Lancashire, Cheshire and North Wales Enginemen's, Boilermen's and Brakemen's Federation, and served as its honorary president for some years.
[2] In his spare time, Forshaw undertook administration for the St Helens Co-operative Society.