MPs have called for the deportation of Saudi dissident Dr Muhammad al-Massari, who runs a London-based radio station broadcasting in Iraq and Saudi Arabia calls for attacks on UK troops.
But there are seemingly no legal or regulatory restrictions to prevent Dr al-Massari from disseminating his messages through his radio, or his website which features videos of bomb attacks on UK troops.
Dr al-Massari has defended the radio station broadcasts
This is despite the fact that they are offensive to most people.
If his satellite station Al-Tajdeed Radio broadcast within the UK it would be subject to the remit of the regulator, Ofcom. But though the broadcasts are apparently put together in London, they are sent by satellite for transmission in Iraq and Saudi Arabia.
Given that Dr al-Massari is not a British citizen, he could be deported by the home secretary on the grounds that his presence in the UK "is not conducive to the public good".
The problem, though, would be where to send him. In Saudi Arabia, he might be liable to torture and, though he was almost dispatched to Dominica in the 1990s, no other destination has been suggested.
Dr al-Massari's website is, of course, accessible from the UK.
The material on it, including beheadings, so-called acts of martyrdom and advice on terrorist warfare, is shocking to many people - but it does not contravene any UK laws.
Given the graphic nature of this imagery, the obvious legislative tools would be the Obscene Publications Acts, 1959 and 1964.
But Peter Robbins, chief executive of the Internet Watch Foundation, said the British authorities were reluctant to invoke them.
"We had discussions with both the police and the government at the time of the beheading of Ken Bigley, images of which circulated on the internet," he said.
"The view was that the wording of the acts, that material must be likely to 'deprave and corrupt', would not be appropriate in this case.
"It is not unlawful to view such material and not unlawful to disseminate it."
Dr al-Massari's website is hosted in Germany, though the domain name is registered to him at a central London address.
But unless the content is considered unlawful, the fact that he is resident in the UK is not likely to help a prosecution.
A website similar to Dr al-Massari's is hosted in the United States.
But that too has remained immune from prosecution, protected by First Amendment rights of freedom of expression.
In Britain, such rights would be overridden by legislation such as the Race Relations Act and Public Order Act.
They cover the stirring up of hatred against an individual or group of people on grounds of colour, race or nationality - not applicable to Dr al-Massari's site.
Encouraging attacks on British troops or the assassination of the prime minister can be lawfully prosecuted and it is likely that the police will be asked to consider whether Dr al-Massari should face charges of incitement to murder or incitement to commit a terrorist attack abroad.
But the evidential threshold would be high and any action against him may have to await the promised legislation making it an offence to glorify acts of terrorism.
Dr al-Massari refused to be interviewed by the BBC but insisted that because his station was not broadcast in Britain, what he said on it had nothing to do with the UK government.