British authorities are still struggling six months after the deadly London suicide bombings to prevent new attacks and counter the militancy that led a group of young Britons to blow up three subways and a red double-decker bus in July.
Prime Minister Tony Blair has made battling terror and cracking down on those who spread radical ideologies a top priority since the July 7 explosions, which killed 52 commuters and the four bombers, three of whom were young Britons of Pakistani descent.
But progress has been slow.
In the weeks after the blasts, police said they were searching for others who might have recruited, trained or supplied the young bombers. But they still have no one in custody in the attacks.
Detectives quickly identified the men, dead in the blasts, whom they suspected of setting off the bombs, but have reported few developments in the investigation since. Efforts to track down other members of the bombing network in Pakistan have led nowhere and the trail may now be cold.
Police had more success rolling up the group that attempted copycat attacks on the capital's transit system two weeks later. Those bombs failed to detonate and no one was hurt. Four men have been charged in the attempts and a dozen others are accused of aiding them.
More broadly, British police and intelligence are trying to retool themselves and boost their capability to prevent more attacks, a task terror experts say is an uphill struggle.
Recruiting Muslims and those who speak languages such as Arabic and Urdu to work as agents, and building networks able to infiltrate terror cells are key, said Alex Standish, editor of Jane's Intelligence Digest.
"The real problem is a lack of information about how militant groups and individuals are organized," he said. "Until we have the appropriate personnel with the right skill set ... it's going to be extremely difficult to talk about an improvement in security."
Sir Ian Blair, chief of London's Metropolitan Police, has warned that more would-be terrorists are at large and planning attacks on Britain.
"We are now [working] more flat-out than we could have ever imagined," he said last month.
After the bombings, Tony Blair announced plans to work with moderate British Muslims on countering radical ideologies that have taken root among some young people.