The arrest of Nick Griffin on Tuesday, one-time host of French National Front leader Jean-Marie Le Pen, was warmly welcomed by Muslims, some of whom said the government should ban the BNP altogether.
Police arrested Griffin, 45, at his family farmhouse in Wales and took him to West Yorkshire, where officers are conducting a major investigation into the activities of BNP members.
Griffin, later released on bail until next March, said: "This is an electoral scam to get the Muslim block vote back for the Labour Party."
Prime Minister Tony Blair's popularity plunged and his trust ratings plummeted after he took Britain to war in Iraq.
Griffin's arrest came two days after police detained the party's 70-year-old founding chairman John Tyndall.
They have now arrested 12 people on suspicion of incitement to commit racial hatred since the investigation began five months ago. None has been charged.
The police inquiry was triggered by a BBC documentary, broadcast in July, which included footage of Griffin giving a speech in the northern town of Keighley in which he railed against Islam and its holy book, the Quran.
Some British Muslims have called
for the BNP to be banned
"This wicked, vicious faith has expanded through a handful of cranky lunatics about 1300 years ago until it is now sweeping country after country," he said.
Other footage in The Secret Agent documentary - watched by about four million viewers - shows another BNP member expressing a wish to blow up mosques with a rocket launcher, and machine-gun worshippers with "about a million bullets".
Another member told how he put dog faeces through an Asian shop's letterbox, while a third described how he beat up a Muslim man. "I'm kicking away. It was fantastic," he said.
Muslims welcome move
Muslims were jubilant at news of Griffin's arrest.
"At last!" said Massoud Shadjareh, chairman of the Islamic Human Rights Commission, which has long urged the government to outlaw the BNP. "This is extremely important.
"It should have been done long ago. There is no place in British society for the bigots of the BNP," he said.
The Muslim Council of Britain (MCB), the biggest lobby group for the country's 1.8 million Muslims, also welcomed the arrests, saying it hoped police would now press charges.
"The BNP has been trying to develop a more polished image and a more sophisticated discourse but the BBC documentary showed that behind that facade, the ugly reality is still the same," said MCB spokesman Inayat Bunglawala.