McManus returned to the UK in 1971 and came to wider attention playing roles such as Harry Carter in The Brothers, and Sam Wilson, a coal miner in the 1973 TV series Sam. He appeared opposite Peter O'Toole in the 1976 TV movie Rogue Male, and starred as a dour Scots police officer, Jack Lambie, in Strangers, a role he reprised as a guest star in the spin-off, Bulman. He also had roles in productions at the National Theatre and the Royal Court Theatre.