In 1964 Tyndall broke with Jordan and founded the Greater Britain Movement (GBM). Around this time Tyndall founded several media projects, including Spearhead magazine and it’s publishing house Albion Press. The magazine was one of the longest-running publications associated with the British nationalist movement, which ran until Tyndall’s death in 2005.
Tyndall would go on to join the National Front (NF), becoming the organization’s vice chairman and then, chairman, from 1972-1980. During this period, the NF experienced its greatest electoral visibility and membership growth. After losing the internal struggle within the NF, Tyndall established the New National Front (NNF) in June of 1980.
In January 1982 Tyndall and associates established the Committee for Nationalist Unity (CNU) as an umbrella mechanism to bring various small British nationalist groups together. Following the CNU’s March 1982 conference, the various organizations agreed to establish the new British National Party (BNP). He served as a chairman and leader of the organization until losing the position to Nick Griffin.
Tyndall died of heart failure on July 19, 2005, at the age of 71, at his flat in Hove, East Sussex.