In August 1998, days after two truck bombs had ripped through the American embassies in Nairobi and Dar es Salaam, I found myself having tea with a quietly spoken Saudi dissident at his home in a suburban street in Dollis Hill, north-west London. Khalid al-Fawwaz had agreed to meet to discuss the terrible events, which had left nearly 300 dead and thousands injured. As we sat cross-legged on the floor sipping sweet tea, he explained his anger at what he saw as the grotesque corruption of the Saudi regime and the deep hurt felt by devout Muslims after the deployment of American troops in Islam's holy land following the Gulf war.

He appeared deeply troubled by reports that his fellow dissident Osama Bin Laden had been associated with the attacks in East Africa. He told me he did not believe that the killing of innocent people was justified in Islam. Al-Fawwaz had good reason to worry: he had been a close associate of Bin Laden's, helping him establish the Advice and Reformation Committee, an organisation devoted to the overthrow of the Saudi regime. Although he had distanced himself from Bin Laden after the Saudi millionaire moved to Afghanistan in 1996 and began calling for jihad against "crusaders and Jews", he still maintained contact, using his office in London to distribute al-Qaeda communiques to the Islamist community. As I left, al-Fawwaz told me that if I ever wanted an interview with Bin Laden, he could help arrange it.

A few days later I called al-Fawwaz to clarify some of the points he had made and the phone was answered by a Special Branch officer, who informed me that the dissident had been arrested. He has been in prison ever since, awaiting extradition to the United States in connection with the American embassy bombings. The al-Fawwaz case has now gone to the House of Lords and he was in court again last month, arguing that the Americans have no hard evidence connecting him with the bombings. On its side, the FBI says that al-Fawwaz was responsible for setting up an al-Qaeda cell in Kenya in the early 1990s and that he purchased a satellite phone later used by Bin Laden's right-hand man, the Egyptian leader of Islamic Jihad, Ayman al-Zawahiri.

In the general hysteria following 11 September, the case of Khalid al-Fawwaz has been highlighted as evidence that Britain has become a safe haven for every bomb-maker and rabble-rouser in the Middle East. Yet in truth, the case is a testament to this country's legal system: al-Fawwaz and others like him have not been shipped off on the first plane to New York to face what would almost certainly be a deeply hostile jury. British judges have insisted on respecting the due process of law.

Khalid al-Fawwaz is one of a number of hardline Islamists held in the UK on terrorism charges awaiting extradition. Among the most high-profile are Ibrahim Eidarous and Adel Abdel Bary, two Egyptian suspects in the East African bombings, who are accused of receiving key documents from Bin Laden associates at a west London fax bureau. An Algerian, Amar Makhlulif, known as Abu Doha, appeared in court on 26 October, accused of involvement in a foiled plot to organise a "millennium spectacular" at Los Angeles airport.

Meanwhile, an especially vicious media campaign has been developed for Yasser al-Siri, an Egyptian dissident who runs the London-based Islamic Observation Centre. Al-Siri is a useful contact for journalists covering the Middle East because of his impeccable contacts within groups at the wilder fringes of Islamic politics. The Daily Mail has called him a "child-killer" on several occasions because of his alleged involvement in a political assassination that led to the death of a seven-year-old girl. The charges, made by the Egyptian government, have never been substantiated to the satisfaction of a British court. On 30 October, al-Siri was arrested for his alleged involvement in providing journalistic accreditation for two suicide bombers who killed the Northern Alliance leader Ahmed Shah Massoud. The arrest appeared to justify the Mail campaign, although at the time of writing, after nearly a week in custody, he has still not been charged with any offence in Britain.

The world of radical Islam can be deeply alienating - cartoon villains with confusing Arab names and violently anti-western views make for unappealing revolutionaries. It does not help that their spokesmen include Abu Hamza, the one-eyed, hook-handed cleric who calls for a holy war from his mosque in Finsbury Park, north London, and Abu Qatada, the giant-bellied Jordanian scholar of jihad whose videos allegedly inspired the 11 September hijacker Mohammed Atta.

The liberal left finds it particularly difficult to support Islamists: their views on women's rights and religious freedoms are unpalatable and the governments they would wish to set up in Egypt or Saudi Arabia would almost certainly be as oppressive as the decadent regimes they replaced. But many fear that the campaign of vilification against these dissidents has already scuppered their chances of a fair hearing.

Many of their cases have been taken up by the campaigning lawyer Gareth Peirce, who represented the Guildford Four and Birmingham Six in their fight for justice. Peirce, who represents al-Siri, Abu Qatada, Makhlulif and Eidarous, believes the paranoia surrounding Islamist suspects is equivalent to that surrounding people accused of Republican terrorist offences in the 1970s. She says she has a deep respect for her clients' religious beliefs and their commitment to the overthrow of governments that torture and murder their opponents. "We are in danger of demonising a whole community and creating an atmosphere where we will have a new series of miscarriages of justice," she says. In the United States and many Middle-Eastern countries, these men would face execution if found guilty, and there is no way of overturning the death sentence in 20 years' time.

It may be that the focus of the nation's Islam neurosis will shift in the light of claims that at least three young Britons have been killed in Kabul and that they were planning to fight as mujahedin. They were members of a home-grown extremist group, al-Muhajiroun (The Emigrants), which has been banned from UK campuses for promoting homophobia and anti-Semitism. Now that his rhetoric has inspired young British Muslims to join the Taliban, Omar Bakri Mohammed, the leader of the group, will no doubt face renewed calls for his arrest. High-level interdepartmental discussions are already under way to investigate whether new laws can be drawn up to outlaw the activities of al-Muhajiroun.

Much has been made of the west's failure to engage with Islam. But it is not enough simply to clutch the Koran to our hearts and selectively quote from passages condemning violence. We need to recognise that no matter how alienating we may find these radical Muslims, they deserve a fair hearing.

Martin Bright is home affairs editor of the Observer