She is the girl of the late Jewish American film actor/director Sam Wanamaker, who come to Britain after being blacklisted during the 1950s; he led a design to rebuild the Globe Theatre in London.

She is probably right-known by the globe-wide audience for her role when Madam Hooch in the film ''Harry Potter and the Philosopher's Stone. She played Clarice, one of a dimwitted twaround sisters of Lord Groan in Gormenghast'', the BBC television adaptation of Mervyn Peake's trilogy. She has as well appeared within the kind of films, programmes, & plays.

Successful television series keep close at hand involved Love Hurts by having Adam Faith and My Family with Robert Lindsay.

Her stage performance around Sophocles' Electra was widely acclaimed.

Wanamaker voiced the CGI character named Cassandra in the Doctor Who episode The End of the World (2005), and might reprise a role in the 1st episode of the 2006 series (tentatively entitled New Earth).

Selected filmography
''Britain's Best Sitcom (2004) (TV series) (narrator) Five Children and It (2004) Harry Potter and the Philosopher's Stone (2001) Adrian Mole: The Cappuccino Years (2001) (TV) My Family (2000) (TV series) Gormenghast (2000) (miniseries) David Copperfield (1999) (TV) Swept from the Sea (1997) Wilde (1997) Prime Suspect4: Scent of Darkness (1995) (TV) (uncredited) Prime Suspect (1991) (TV) Edge of Darkness (1985) (miniseries) Inside the Third Reich'' (1982) (TV)