Background
Lonnen was born in Bournemouth where he attended the Stourfield School and the Hampshire School of Acting.
Lonnen was born in Bournemouth where he attended the Stourfield School and the Hampshire School of Acting.
His most prominent roles include Willie Caine in the cold-war spy drama series The Sandbaggers (1978-1980), and also as Harry Brown in the television miniseries Harry"s Game (1982). At 19 he gained his first professional acting job at a theatre in Belfast. He then appeared in repertory theatre in English towns and cities including York and made his first television appearance alongside John Alderton in Emergency – Ward 10.
His early acting appearances include television series such as Mrs Thursday (1966), The Power Game (1966) and Market in Honey Lane (1967), and a brief role in the film Zeppelin (1971).
He then had a semi-regular role in the British crime drama series Z-Cars between 1972-1977, and also appeared in the cult television series Doctor Who ("Frontier in Space"). Lonnen played one of the leads in the 1978 Independent Television espionage series The Sandbaggers, in which he played Willie Caine (aka "Sandbagger 1").
The Sandbaggers ran for three series until 1980. After playing the lead role in an episode of the Independent Television anthology series Hammer House of Horror in 1980, Lonnen"s next lead role was in the 1982 Independent Television mini-series Harry"s Game, based on the novel by Gerald Seymour, playing Harry Brown, a British agent sent to Northern Ireland to smoke out the Ireland Republican Army assassin of a cabinet minister.
In 1984, Lonnen went on to star in yet another spy-themed drama series, The Brief, in which he played a British barrister who travels to Germany to represent a British soldier accused of spying and treason.
Aside from his lead roles, Lonnen also continued to appear in guest roles throughout the 1980s, including episodes of The Gentle Touch, Tales of the Unexpected, Lovejoy and the French film Mangeuses "Hommes. In 1990, Lonnen played Detective Inspector Alex Vale in the Independent Television detective drama series Yellowthread Street, which was set in Hong Kong. Based on the novels by William Leonard Marshall, the series ran for 13 episodes.
Throughout the 1990s, Lonnen continued to make guest appearances in various television series and even voiced several characters in the children"s animated series Budgie the Little Helicopter.
In 2001, he had a recurring role in the Independent Television police series The Bill. He appeared in several episodes of the Canadian sci-fi series Starhunter as well as a recurring role in the short-lived revival of the Independent Television soap-opera Crossroads.
Since the 1960s, Lonnen has performed in a variety of stage roles, including drama, comedy and musicals.