In 1942 he moved from Narrandera to Sydney and worked in the state public service in technical education.
In 1978, sitting Liberal member Laurie McGinty lost preselection to future Premier Nick Greiner and contested the seat as an independent.
The split in the conservative vote allowed Britt to win narrowly in this normally comfortably safe Liberal seat.
However, a redistribution ahead of the 1981 state election erased Britt's majority and made Willoughby notionally Liberal.
Despite this, Britt nominated for another term, and was narrowly defeated by Liberal challenger Peter Collins.