A woman who started her political career in Hove today became Westminster's youngest MP.

Last May, Sarah Teather was dropping Liberal Democrat campaign leaflets through letterboxes in Brighton and Hove.

At 3am today the 29-year-old won the north London seat of Brent East in a by-election, over-turning a Labour majority of 13,047.

The decisive 1,118-vote victory, a swing of 29 per cent, has sent shockwaves through the Government.

It is the party's first by-election defeat since storming to power in 1997, and a particular blow as East Brent has traditionally been a rock solid Labour seat.

But today in Brighton Miss Teather's friends were celebrating.

Coun Paul Elgood, Brighton and Hove City Council's Lib Dem group leader, said: "It's tremendous news. Sarah is a close friend.

"I've already had a message from her telling me how over the moon she is, and that she will be down for the conference."

Last year Miss Teather, who lived in Wilbury Road, Hove, was a member of the local Lib Dems while working as a research chemist in the Pavilion Buildings.

The win is a huge boost for the annual party conference, which starts in Brighton this Monday.

David Watkins, councillor for Brunswick and Adelaide ward, said: "We're absolutely thrilled. It's fantastic, especially for a local woman. Our loss has turned out to be Brent's gain."

Accepting her victory over Labour MEP Robert Evans, Miss Teather said: "Tony Blair, I hope that you are listening tonight. The people of Brent have spoken for the people of Britain."