British National Party activists have confessed to racially motivated crimes including an assault on an Asian in a BBC undercover documentary.
Steve Barkham claims to have attacked this Asian man
BNP member Steve Barkham told reporter Jason Gwynne how he kicked and punched a man during the 2001 Bradford riots.
The Secret Agent also shows the party's leader Nick Griffin condemning Islam as a "vicious wicked faith".
Mr Griffin accused the BBC of selective editing and said his full speech had discouraged attacks on communities.
BBC producers say the material will be handed over to the police and the Crown Prosecution Service.
Mr Gwynne spent six months infiltrating the BNP's West Yorkshire branch with the help of former local organiser Andy Sykes, who turned mole for anti-fascist group Searchlight.
In the documentary, footage recorded at a meeting in Keighley shows BNP leader Mr Griffin saying it was important to stand up and act for the party or "they (Muslims) will do for someone in your family".
"For saying that, I tell you, I will get seven years if I said that outside."
He calls Islam a "wicked, vicious faith" that "has expanded through a handful of cranky lunatics" and "is now sweeping country after country".
Another member, Stewart Williams, says he wants to "blow up" Bradford's mosques with a rocket launcher.
BNP council candidate Dave Midgley is shown saying he squirted dog faeces through the letterbox of an Asian takeaway.
In the film, Mr Barkham says he beat an Asian man during the Bradford riots.
But, he says, he was not prosecuted as his victim was unable to identify him from police photographs.
A West Yorkshire Police spokeswoman said: "We haven't yet seen the programme, we have spoken to the programme makers and will be investigating the claims made to identify what, if any, offences may have taken place.
"We ask anyone with further information about any of the alleged crimes to contact us."
Mr Griffin later said Mr Midgley and Mr Barkham would be expelled from the BNP.
And Mr Williams would face an internal disciplinary tribunal in connection with his comments, he added.
The Muslim Council of Britain (MCB) has welcomed the BBC investigation.
It urged the government to introduce legislation outlawing incitement to religious hatred, or discrimination on religious grounds.
Iqbal Sacranie, secretary-general of the MCB, said: "We look forward to the Crown Prosecution Service and Director of Public Prosecutions confirming that they will look at the programme to see whether any existing criminal offences have been committed."
Mr Griffin accused the programme makers of selectively editing a speech he delivered in the film and challenged the authorities to prosecute him.
"It's still not illegal to criticise Islam", he said.
"If Mr Blunkett wants to put me on a show trial about whether we're entitled to warn about the dangers of Islam, I will be absolutely delighted."
Any jury would see the full speech, in which he states that the BNP is not targeting individuals or communities, he added.
The BBC was failing in its charter terms to represent the views of BNP supporters who now represented 5% of the electorate, claimed Mr Griffin.