He is best known for his roles in Survivors as Charles Vaughan, Only Fools and Horses as Alan Parry, Outside Edge as Dennis Broadley and as Consultant General Surgeon Mr Rose in the ITV1 medical drama The Royal.
[2] Some of his many film and television roles include Fall of Eagles (1974), Special Branch (1974 series 4, ep12), Edward the Seventh (1975), Survivors (1975–77), The Eagle Has Landed (1976), Bad Blood (1981), The Scarlet Pimpernel (1982), as William Knox D'Arcy, the Australian oil pioneer in Persia, in Reilly: Ace of Spies (1983), Rumpole of the Bailey (1983–92), Mapp and Lucia (1985–86), Only Fools and Horses (1989–92), Batman (1989),[3] Bernard and the Genie (1991), Red Dwarf (1 episode, 1993), Richard III (1995), Evita (1996),[4] The Opium War (1997), Rebecca (1997) Heartbeat (2002) and The Royal (2003-2011).
[5] Lill twice appeared in the BBC's science fiction series Doctor Who: as Dr Fendelman in the 1977 serial Image of the Fendahl and as Sir George Hutchinson in 1984's The Awakening.
In 1980 he appeared in the role of Josef Merhart, a member of an organised crime syndicate involved in a silver bullion robbery in the hard-hitting British police drama The Professionals; the episode titled "Hijack".
He appeared in Red Dwarf, playing a rogue simulant in "Gunmen of the Apocalypse", in Bertie and Elizabeth as Clement Attlee (2002) and from 2003 until 2011 Lill starred in the ITV1 drama The Royal as Consultant General Surgeon Mr. Rose.