Republicans take Ted Kennedy's seat in Massachusetts in historic upset

A little-known Republican state legislator won Edward Kennedy's old seat in the US Senate in Massachusetts in what appeared to be a massive protest vote against the party that controls both chambers of Congress and the White House.

Mr Brown made up a 30 percentage point deficit to defeat Martha Coakley, the state's Attorney-General.

"This is a huge wake-up call for the Democrats, for the Obama Administration and the country. America is fed up of the arrogance coming from Washington," said Andy Card, the White House chief of staff in the George W. Bush Administration.

The Democrats will be damaged by the by-election defeat, which deprived them of the 60-seat "super-majority" that allows them to overcome Republican filibusters in the 100-member US Senate.

Scott Brown, a lawyer, military officer and former male model, has promised to use his Senate vote to defeat the Democrats' healthcare reform, which was on the brink of passage after decades of trying.

Democrats pledged to try to push through healthcare reform despite the loss, but they risk a popular backlash if they do so.