Britain's government has published a list what it calls unacceptable behaviour, behaviour which could see foreign nationals deported or barred from the country.
The document from Home Secretary Charles Clarke followed a series of proposals outlined earlier on Friday by Prime Minister Tony Blair in response to last month's bomb attacks on London.
Banned acts would include those which:
- Foment terrorism or seek to provoke others to terrorist acts.
- Justify or glorify terrorism.
- Foment other serious criminal activity or seek to provoke others to serious criminal acts.
- Foster hatred which may lead to violence against specific communities in Britain.
- Advocate violence in support of particular beliefs.
- Anything else the government considers to be "extreme views that are in conflict with the UK's culture of tolerance".
Such views could be aired in the following ways:
- Writing, producing, publishing or distributing material.
- Public speaking, including preaching.
- Running an internet site.
- Using a "position of responsibility" such as a teacher, community or youth leader.
Clarke, who interrupted a holiday to draw up the document, defended the government's actions.
"In the circumstances that we now face, while treading carefully in areas that relate to free speech, it is right to broaden the use of exclusion and deportation powers to deal with those who foment terrorism, or seek to provoke others to commit terrorist acts," he said.
"I believe that these powers need to be applied more widely and systematically both to people before they come to the UK and when they are here."