After leaving Bishop Creighton School, he became a clerk on the London and North Western Railway, he joined the Foot Guards when the First World War broke out, later transferring to the Royal Artillery.
He was wounded and invalided home, where army doctors advised him to find a more active occupation than his previous office job in order to improve his health.
A trade unionist since 1912, he joined the Transport and General Workers' Union and rose rapidly through the ranks.
During the Second World War he commanded a Home Guard battalion and was TUC representative on the Territorial Army Advisory Committee.
Tiffin's short period of office was troubled by a dock strike and a dispute between the TGWU and the National Amalgamated Stevedores and Dockers.