Elected at the 1989 general election to the inaugural multi-member single electorate unicameral Australian Capital Territory Legislative Assembly representing, initially, the No Self-Government Party, Prowse then sat as an independent, before joining the Liberal Party.

[2] Prowse retrained as a naturopath and rose to political prominence as an anti-water fluoridation activist.

However, Prowse left this group on 31 July 1990 and sat out the remainder of his term as a member of the Liberal Party.

[5] Prowse held this title during the term of his first Assembly;[2] and did not seek re-election at the 1992 general election.

[6] During his term in office, Prowse travelled to Thailand where he was bitten by a holiday resort monkey; and later told a press conference he feared that he might have contracted the rabies virus.