Equality campaigners have called on Home Secretary Theresa May to prevent two extreme anti-Islamic activists from entering Britain, after they were invited to speak at a rally for the far-right English Defence League in London later this month.
US bloggers Pam Geller, who co-founded the anti-Islamic American Freedom Defence Initiative, and Robert Spencer who founded another right-wing extremist group, Jihad Watch, were invited by EDL leader Tommy Robonson to address the rally on 29 June in Woolwich - the inner London suburb where soldier Lee Rigby was murdered.
Geller was behind a recent inflammatory advertising campaign on the New York subway, which featured posters depicting Muslims as "savages" and declaring: "In any war between the civilised man and the savage, support the civilised man."
When the district authorities vetoed the campaign, Geller cited her right to "freedom of speech" and won a court ruling allowing her to place the adverts in 10 subway stations. She later complained when all the adverts were defaced "within an hour".
Geller led protests against the construction of an Islamic centre at Ground Zero in New York and, with Spencer, founded the pressure group Stop the Islamisation of America.
She is a vocal opponent of President Obama, claiming his birth certificate is a forgery and calling him "a third worlder and a coward" and an "appeaser of his Islamic overlords".
Nick Lowles, founder of the anti-extremist group Hope Not Hate, said: "Understandably, their organisation is considered a hate group and that's why we are writing to the home secretary asking that she stops them from entering the UK.
"Just like the EDL, Geller and Spencer blame all Muslims for the actions of a few extremists. Join us in telling the Home Secretary that Geller and Spencer are not welcome here."
The murder of Rigby outside Woolwich barracks on 22 May prompted a spate of vandalism and arson attacks on mosques.
An Islamic centre in Muswell Hill, north London was set alight, and emergency workers found the letters "EDL" scrawled on the burned-out ruins. Mosques have been attacked in Grimsby, Gloucester and Rhyl, while a policeman was among four people wounded when a knifeman went on a stabbing spree inside a mosque in Birmingham.
In 2010 Christian fundamentalist preacher Terry Jones was prevented from addressing an EDL rally in Luton after pressure from anti-extremism campaigners.
Jones, a Florida pastor, caused violent protests across the Muslim world in 2010 after threatening to burn copies of the Koran on the anniversary of 9/11.
He also achieved notoriety for his role in promoting the anti-Islamic propaganda film Innocence of Muslims, which sparked riots in at least seven countries incuding Pakistan and Libya, where it triggered the killing of the US Ambassador Chris Stevens.