By Dominic Casciani
BBC News Online community affairs reporter
Many Muslims are increasingly troubled by anti-terrorism operations. One public meeting this weekend showed how for some that concern is turning to anger.
Ashfaq Ahmad: 'Family nightmare'
Ashfaq Ahmad told us he was not used to speaking in public - he is after all a retired civil servant, more practised in quietly doing his work behind a desk in Whitehall.
But now he believes it is the time to speak out, such is his conviction that his son is an innocent victim of the war against terror.
On Thursday, 30-year-old Babar Ahmad was arrested by anti-terror police and told he was facing extradition to the United States.
He had started the day as an IT officer at Imperial College, London. He ended it an international terrorist suspect, allegedly in possession of information on US warships. Among the other allegations against him are that he has solicited support for terrorism in Chechnya and Afghanistan.
This is not the first time Babar Ahmad has been in custody - he was arrested under the Terrorism Act and later released without charge in December 2003.
His supporters allege he suffered injuries during his arrest - and still suffers pain today.
This weekend, he had been due to talk at a public meeting in south London called "Stop Police Terror". But his extradition arrest meant his father would be speaking in his place.
"You must all think that my son is a cold-hearted monster. He has always been a law-abiding citizen," Ashfaq Ahmad told an audience several hundred strong.
"My family are living in a nightmare; you can't imagine the pain or suffering that we are going through.
"Do you really believe that a young man from Tooting was planning a terrorist attack against a [US] aircraft carrier?"
Sunday's public showing of support for Babar Ahmad was not a one-off eruption of emotion against a single arrest.
In the past year, there have been similar meetings debating anti-terrorism policing in other areas of London, Luton, Manchester, Birmingham, Bromley and even Gloucester.
Injuries: Supporters say Babar Ahmad hurt during previous arrest
But as the security services arrest suspects, the sense of community security appears to be diminishing.
Among many Muslims - particularly the young - the collective sense of bewilderment which came with the September 11 attacks is now giving way to resentment and anger.
Today, the most provocative speakers describe the police and MI5 as aggressive tools of state-sanctioned Islamophobia.
It's a charge that the police vehemently reject. Assistant Chief Constable Rob Beckley, the spokesman on faith issues for the Association of Chief Police Officers, recently appealed directly for community support.
He said the police neither target nor seek to "criminalise" any community - they only targeted criminals. Only with the help of communities affected by terrorism, could terrorists be defeated, he stressed.
Writing in the Muslim News, he said: "I recognise that there is deep anxiety about the current events and the way they are reported."
"There are concerns about unfair and careless linking of Muslims and terrorism, there are fears about indiscriminate use of anti-terrorist powers and, should such an event happen, apprehension about a possible backlash against Muslims.
"Our links with Muslim communities are not always as good as they could be, leading to lack of understanding of issues and events, and misunderstandings on both sides."
But he appealed for the police to be given a fair voice to explain what is going on.
"When controversial issues arise about policing, and questions are asked, especially in a fast moving situation, please pause for a moment and give us an opportunity to respond, engage in discussion and explain from our perspective," he said.
"The police often bear the brunt of criticism that should be directed at others, such as newspapers or broadcasters, for misreporting or distortion, accidental or deliberate."
But nevertheless, Sadiq Khan, a lawyer and legal affairs spokesman for the Muslim Council of Britain, said anti-terror laws were damaging community relations and, worst of all, draining support for the police.
"If I was writing a handbook about how to recruit more Muslims into the police [as forces say they would like to], I would not go around criminalising their communities and demonising their religion," he said.
Campaigning: More groups emerging
There have been 600 arrests under anti-terrorism laws since the September 11 attacks. Of these, 90 people have been charged and a dozen actually convicted.
Police officers say this doesn't represent the true picture. A further 120 have been charged with other crimes, such as fraud, immigration or firearms offences and 54 have been found to be in breach of immigration rules. On top of that, more than a quarter of the arrests were in relation to probes into Northern Ireland paramilitary groups.
While Muslim campaigners point to official figures showing a 300% rise in stops and searches of British Asians, police officers say this rise only actually amounts to a few more people a day.
But news tends to travel quickly among Muslim communities - and so do the latest theories about what is going on.
So a year ago, just a few left-wingers described Muslims as "the new Irish" - drawing a parallel with how some members of that community felt they were unfairly singled out during the IRA's campaign.
Today you will find far more ordinary Muslims, such as Ashfaq Ahmad, share that opinion.