The British National Party achieved its most significant electoral breakthrough last night when it won two seats in the European Parliament.

In a result that hands the far-right party an international platform, Nick Griffin, the BNP leader, clinched a seat in the North West and the party also gained a MEP in Yorkshire and the Humber.

The party had capitalised on the expenses furore during the election campaign but mainly benefited from the Labour meltdown, winning key votes from its traditional strongholds.

In the North West, Mr Griffin gained the eighth MEP seat, although his party gained fewer votes than in the 2004 election. Labour lost 240,000 disaffected voters. In Yorkshire the BNP won almost 10 per cent of the vote, most of it from Labour.

The result sent shockwaves through the mainstream parties, with the BNP undoubtedly poised to use its win to claim that it has political legitimacy.

Andy Burnham, the Health Secretary, described the win as a “sad moment in British politics”. Both Gordon Brown and David Cameron have been outspoken recently about the BNP.

The party polled very well in Labour’s traditional working class strongholds, achieving 16 per cent of the vote in Barnsley, nearly 12 per cent in Doncaster and 15 per cent in Rotherham. It received 120,139 votes in total.

The result will put further pressure on the Prime Minister to stand down and there was speculation last night that it would increase the chances of a leadership challenge.

As Nick Griffin stepped forward to deliver his victory speech, the other winning candidates stepped down from the podium in protest.

The BNP leader told supporters that hundreds of thousands of voters had given their verdict on the old, liberal consensus, had ignored the 'lies' of popular newspapers and "truth, justice and freedom are once again flowing over this country. He added: "It is a great victory. We go on from here".

Mr Griffin said that his party had made political history. “I think it means there is now huge pressure on Gordon Brown to go. The British public have done this in the teeth of a most disgraceful vicious lying press campaign against the BNP. I do not believe it was a protest vote in any way. They voted for our policies. It is an absolutely fantastic result.”

The party's winning candidate in Yorkshire, Andrew Brons, 61, said that his election was the first step towards Britain separating from the “EU dictatorship”. “Despite the headlines, despite the money, despite the misrepresentation, we have managed to win through.”

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