Nick Griffin told a meeting of party supporters that Muslim teenagers were encouraged by the Koran to make white girls pregnant “so that the faith can expand”.

Mr Griffin, 45, of Llanerfyl, Powys, is on trial at Leeds Crown Court, where he denies four offences of conduct intended to stir up racial hatred.

The charges against the BNP chairman and eight similar charges against Mark Collett, 24, a senior party member, are linked to speeches made by the two men that were secretly recorded by the BBC.

Speaking to a rally at a pub in Keighley, West Yorkshire, in January 2004, Mr Griffin said that Asian crimes against whites, including paedophile drug rapes, had turned Britain into “a multiracial hell-hole”.

Muslim violence would expand to cover the UK, he claimed, “as the last whites try and find their way to the coast”. A vote for the BNP would “ensure the British people realise the evil of what these people have done to our country”.

Opening the case for the prosecution, Rodney Jameson, QC, told the jury of eight men and four women that they were not being asked to pass judgment on the politics of the BNP or of the two defendants.

“Your decision will not be a mini-referendum on what you think about the BNP,” he said.

He said that the Crown did not claim that people should not be allowed to debate the “very sensitive issues” of race or immigration. “It is not the purpose of this prosecution to stifle legitimate political debate,” he said. But the law did not allow the use of threatening, abusive or intimidating words with the intention of stirring up racial hatred, or whereby racial hatred was likely to be stirred up.

The jury were told that they would be shown film footage of the speeches by the two men in West Yorkshire, between January and May 2004, which went “far beyond robust comment”.

Mr Jameson said that Mr Griffin tended to refer to his targets as Muslims, not Asians, because he was aware that inciting religious — as opposed to racial — hatred was not a crime. “You may conclude that Griffin uses the words Asian, Muslim, and occasionally Paki, interchangeably, and that his target is the Asian Muslim community throughout.”

During his speech in Keighley, Mr Collett, of Rothley, Leicestershire, said that people in Bradford and Keighley were “living in hell” because of rapes and muggings by Asian gangs. “They don’t go looking for Asian victims, they go straight to the whites,” he said. “They are the racists and they’re trying to destroy us. If you want to get these people out and stop asylum-seekers coming in, vote for the BNP. Let’s show these ethnics the door in 2004.”

In another speech, Mr Collett called asylum-seekers cockroaches. “They multiply rapidly and they take everything. A high proportion of them are actually terrorists,” he said.

Mr Jameson said that the speeches aimed “to build a fear and resentment of Asian people”. He acknowledged that Mr Griffin commented on “legitimate matters for public consideration”, but urged the jury to look at how and why Mr Griffin said what he said. “Freedom of expression is an important right but it cannot be unfettered. No society can permit disapproval of another race to be expressed in such strong terms that hatred be stirred up against people on the basis of race or ethnicity.”

The two men deny the charges. The trial continues.

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