Republican Scott Brown has won a shock victory in the race for the US Senate seat in Massachusetts left vacant by Democrat Edward Kennedy's death. The result is a huge blow to President Barack Obama, whose healthcare reform programme is now in doubt. Democrat Martha Coakley conceded she had lost the race after early results gave Mr Brown a healthy lead. The Republican win has robbed the Democrats of their filibuster-proof 60-seat majority in the Senate. This will make it much harder for Mr Obama to pass a healthcare reform bill - the most important domestic policy objective of his first year as president. 'Senator Beefcake' The BBC's Paul Adams, in Boston, says Ms Coakley's defeat is a humiliating defeat for the Democrats, and a deeply unwelcome anniversary present for President Obama exactly one year after his inauguration. He adds that it is one of the biggest political upsets in years - in a seat held for almost half a century by Edward Kennedy, a Democratic Party colossus, who died last year. In his victory speech, Mr Brown, 50, said that the voters of Massachusetts had "delivered a great victory". He said: "Tonight, the voters of this commonwealth defied the odds and the experts." He also made clear he would join his Republican colleagues in trying to block President Obama's healthcare reform proposals. Mr Brown led Ms Coakley by 52% to 47% with virtually all votes counted; a third candidate got less than one per cent. Dubbed Senator Beefcake in the US media, Mr Brown is a lawyer and former model who posed almost naked for Cosmopolitan magazine in the 1980s while in law school. 'No sugar-coating' After conceding the election in a telephone call to Mr Brown, Ms Coakley told her supporters she was "heartbroken at the result". Sen Robert Menendez, head of the Senate Democrats' campaign committee, said he had "no interest in sugar-coating" the result. "There is a lot of anxiety in the country right now," he added. "Americans are understandably impatient." President Obama had campaigned personally on behalf of Ms Coakley. Analysts say the race should have been an easy win for her in a state which has traditionally voted for Democratic candidates for the US Senate. Lacklustre campaign Just weeks ago, Ms Coakley, the state attorney general, had a double-digit lead in polls and seemed destined to win. But a lacklustre campaign allowed her Republican opponent to seize on voter discontent and overtake her in the final stretch. Voters flocked to the polls through the snow and rain that fell all day on Tuesday. Ms Coakley said she had received a telephone call from President Obama, who told her: "We can't win them all." Senior Republican figure Mitt Romney said the vote heralded a political sea-change. "This is really a referendum on the Barack Obama agenda and I think a way of working in Washington, which is kind of an arrogant approach to politics in this country," the former presidential candidate told Fox News. Third major loss White House spokesman Robert Gibbs said President Obama had called Mr Brown to congratulate him and to tell him he was looking forward to working with him. Senate Democratic leader Harry Reid said Mr Brown could take his seat "as soon as the proper paperwork has been received" from Massachusetts officials. Correspondents say the vote does not bode well for the Democrats ahead of November's congressional elections, and that if they cannot hang on to a party stronghold such as Massachusetts they could be vulnerable almost anywhere. The result comes amid opinion polls showing nearly half of Americans think President Obama is not delivering on his major campaign promises. It was the third major loss for Democrats in state-wide elections since he became president: Republicans won governors' seats in Virginia and New Jersey in November. Source: BBC