The Muslim community could do more to help identify would-be jihadis, a police chief has said.
Sir Norman Bettison, the Chief Constable of West Yorkshire Police, said that while he is conscious there is a fine line between winning the support of the Muslim community and alienating it, there was also a need for the community to work with the police.
"I'm looking for the community to work much more closely with the police in identifying young people that they have concerns about in terms of the people that they're mixing with, the sort of websites that they're going on to and the material that they're reading," he said.
"Now that information can only come from the community itself."
Sir Norman was speaking during an interview for the BBC Two series Generation Jihad - the first episode of a three-part series is being screened tonight.
He told the programme the Muslim community could do more to help identify potential terrorists in its midst.
"I think we have to be alert and conscious of the risk that's ever present and prepared to interdict and prepared to share information," Sir Norman said.
"So the community as a whole could do more and the Muslim community is a part of that."
Three of the 7/7 London bombers came from West Yorkshire and the area is also home to Hamaad Munshi, Britain's youngest convicted terrorist.
Sir Norman, who is the Association of Chief Police Officers' representative for policy on tackling violent extremism, said "Generation Jihad" was likely to remain a problem for some time.
"I think it's a generation of treatment to prevent the infection spreading and I think that will take us probably 20 years," he said.
The series, which is presented by Peter Taylor, looks at why young men have turned their backs on the country where they were born.
Although they represent a tiny minority of the Muslim community, they now constitute the single biggest threat to Britain's national security, Mr Taylor said.