After a brief spell at the Italia Conti Stage School, he joined a repertory company in Cork before completing his training at RADA.
He then worked in radio and television,[2] as well as being a member of Hatch End Players.
Lambert played the role of athlete Ken Sparten in the 1969 SF/horror film Scream and Scream Again, and in more recent years provides the voice of Mr Curry in The Adventures of Paddington Bear television series and also Papa in the Dolmio pasta sauce puppet commercials.
He also appeared as Operative Chris Granger in the UFO episode "Computer Affair" and contributed extensively to the magazine partwork Story Teller published by Marshall Cavendish, consisting of a fortnightly magazine and a cassette tape featuring children's stories.
In 1980, he played the character of Hardin in the Doctor Who story The Leisure Hive, in addition to providing the voice of the Priest Triangle in the 2021 episodes War of the Sontarans and Once, Upon Time.