The UK's international reputation has suffered "real damage" as a result of the British National Party gaining their first seats in the European Parliament, politicians, unions and race relations groups said today.
Labour MEP for London Claude Moraes said that a threshold had been crossed after the far-right party won two seats yesterday.
Speaking at a Unite Against Fascism press conference in Westminster, Mr Moraes also acknowledged that the BNP had "jumped upon" Gordon Brown's slogan "British jobs for British workers" during the election.
BNP leader Nick Griffin picked up the seat in the North West of England region and Andrew Brons won a seat in the Yorkshire and Humber region.
Mr Moraes said: "There is real damage here to Britain because we have never elected fascists in a national election.
"Fascists in the European Parliament where I sit have long wanted members from Britain to join this transnational group so for those reasons there is deep concern that we have now crossed that threshold.
"There was a long period in which we could have said neo fascists would not be elected in Britain to represent us in an international parliament."
He said that many people would today be viewing Britain as a "nastier" place than they had prior to yesterday's election.
Mr Moraes said Labour had suffered as a consequence of the expenses scandal but acknowledged the BNP had manipulated Gordon Brown's British jobs slogan.
He explained: "That phrase was jumped upon by the BNP, they are trying increasingly to look at what mainstream politicians say to embarrass the politicians as a way of getting support."
The BNP wins came as the party appeared to attract significant numbers of disaffected Labour voters.
Frances O'Grady, TUC deputy general secretary, told the press conference the election results had to be viewed as a breakthrough for the BNP.
But she argued that in many parts of the UK the far-right party had been beaten.
She said: "It seems we are living in very strange times, we are commemorating the D-Day landings on Saturday and electing fascists on Sunday."
She added: "The BNP are not a normal democratic party, they are a fascist party with no place in British democratic life."
Mr Griffin said that his party winning two seats would herald a "huge change in British politics".
Speaking yesterday, he said: "The most demonised and lied about party in British politics has made a massive breakthrough. The public have had their say in a democratic election and we should respect that."
But Lee Jasper, from the National Assembly Against Racism, said the election posed a huge threat to the black community.
He explained: "It's a critical moment. We are suffering a national crisis in confidence in race relations."
Urging mainstream political parties to come together to fight the BNP, he said: "We must ensure this is not used as a platform or springboard for the next General Election.
"The election of the BNP is a massive threat to the black community nationwide."
Sabby Dhalu, from Unite Against Fascism, warns that whenever the BNP were voted in racist attacks increased in those areas.
She added: "The BNP stands for virtually every form of hatred you can think of."
Peter Hain, the newly-appointed Welsh Secretary, released a statement via United Against Fascism which read: "It's a shameful stain on Britain that we now have racists and fascists representing our country.
"It is vital that everyone now isolates and confronts the BNP and works with United Against Fascism to defeat them."
Former London mayor Ken Livingstone released a statement which read: "The economic crisis and abuse of MPs' expenses have provided fertile ground for the extreme right.
"It is no surprise in these circumstances to see an electoral breakthrough for the BNP, a fascist party in Britain.
"The BNP claims to be a normal political party. In fact, they are 21st century Nazis. As in the 1930s, they exploit people's anxieties in an economic crisis to scapegoat minorities and ultimately threaten all our democratic freedoms."