[5] Her most memorable role was that of Lesley Bainbridge in the BBC sitcom Brush Strokes, which at its peak, was watched by over 15 million people with the British tabloids avidly following the storyline.
In the 1987 episode of the TV series "Tales of the Unexpected" Thomson played the role of hotel maid Elly Somerton alongside Topol who starred as the lead character Professor Max Kelada.
Dozens more appearances in film and on television followed, often as a character actress, such as her role as a society reporter in The Princess Diaries 2: Royal Engagement (2004).
In 1997, she took on the part of Lady Chiltern in An Ideal Husband, of which the Theatre Record said "Others have played this pure, cool, idealistic, demanding role with more authority and finesse, but she is simply right for it".
[11] During 2008, Thomson had a recurring role in ITV's detective show The Bill, as barrister Naomi Woods, wife of DC Jacob Banks.