The telephones in his Hammersmith office chirped incessantly yesterday with the voices of Arab dissidents, liberals and general opponents of the region's universally autocratic governments, worried that they are all now in danger in the country that has been a safe haven for so many years.
Algerians, Bahrainis, Egyptians and Tunisians are at the top of the list of activists whom the British government, arms-dealers and industrialists, in general, would like to see vanish from the London scene; their governments have put strong pressure on Britain to silence these largely pacific yet politically effective operators, who deal in words rather than bombs and bullets. In each case, these pressures have been sympathetically received. "Even tiny little Bahrain puts the wind up you," says the editor of al- Quds.
The haven of Arab opposition is north-west London - Willesden (the Saudis), Cricklewood (the Bahrainis), Harlesden (the Tunisians). Even Joseph Conrad's ineffective and seedy secret agent would have turned his nose up at the dedicated, somewhat bookish and unromantic existence of these exiles behind mock-Tudor frontages. Information - newsletters, pamphlets, bulletins, newspaper articles, and in Mohammed al-Masari's case, faxes - is what these Arabs deal in.
In the paranoid world of Arab leaders, information is as feared a weapon as Semtex. Last week, Mr Masari and I talked in his ground-floor flat as the faxes buzzed towards the Gulf. I left loaded with his facts and figures and stories of Saudi incompetence, financial mismanagement, debt, corruption and immorality - the basis of the material he transmits into the Kingdom.
Mr Masari is watched by British security, and there is little doubt that his phones and faxes are monitored and translated by MI5. Mr Masari and others like him, however, are not worried by these watchers - rather the reverse. They have received little (until Michael Howard's expulsion order, that is) in the way of official or other British harassment: some advertising was refused; a telecommunications firm dropped its contract for no good reason; a London think-tank refused to write a report on security risks in the Gulf.
No, their main fears until now have been of reprisals against them by agents of their home governments. Ahmed Fahmi, of the Egyptian Action Group, which monitors human rights and political shenanigans back home - last month's charade of an election, for example - is concerned about reports of squads of Egyptian hit men here.
Mr Masari's expulsion, if it goes through, is probably more of a worry to him than threats of violence, just as it is to the Bahraini Freedom Movement. This group, more secular than Islamic, have so irritated the despotic little regime back home (which has locked up and deported thousands of Bahraini citizens merely for asking for the restoration of their constitution suspended 21 years ago), that Bahrain has hired MPs and PR firms to burnish its tattered image and persecute its opponents.
The most controversial figure here, after Mr Masari, is probably Dr Rachid Gannouche, leader of the opposition Tunisian Nahda, or Renaissance Party. He was jailed by the late President Bourguiba, released, accused of involvement in a bomb outrage in a Tunisian resort, but cleared by the courts, and later fled to France and then on to Britain.
Britain has hundreds of millions of pounds invested in Tunisia and would be delighted to pay a first-class fare for Dr Gannouche on Tunisian Airlines, or even back to the Sudan, whence he came. But he has been granted asylum here and concentrates on giving lectures on the role of Islam in the modern world. Dr Gannouche takes no chances. He does not give out his address or phone number, and meets journalists only rarely. When he does give interviews, it is usually in parks or hotel coffee shops.
The Tunisians are rightly nervous. Early last year they discovered that their rubbish was being collected by cars with Algerian diplomatic number plates - Tunisia has been a haven for Algerians on the run from their violently shaken homeland. They have now, like many other Arab groups, invested in shredders.
Bumping off irritants abroad is an old Arab custom. The Arabs here, mostly of Islamic tendencies, well recall the battleground London became in the late Seventies, when different Palestinian and Iraqi groups fought and killed each other in London's W1. British security became much tighter and more expert in its dealings with the fast-growing Arab community. The summary way the SAS dealt with the Iranian Embassy siege in 1980 inculcated a powerful respect among Middle Easterners for law-enforcement in this country.
The murder of a popular Palestinian cartoonist, Naji el-Ali, in Chelsea in 1987, however (widely believed among Arab observers to have been ordered by Yasser Arafat) and the recent murder of a Libyan in Bayswater (which most Arabs still reckon has deep in it the hand of Colonel Gaddafi), remind activists of their vulnerability.
According to Azzem Sultan, a young Jordanian Islamist who runs a human rights group, "Liberty for the Muslim World", if this government can remove Mr Masari it can remove anyone. But worse, in my view, knowing the Arabs and the mentality of the region that most never quite shake off, is the now heightened fear that not only is Britain no longer a safe refuge, but that the authorities here might turn a blind eye to the activities of counter-opposition groups hired by Arab embassies. Suspicion will grow among London's Arabs, about one another, about Britain's susceptibility to coercion, about Britain's "Muhabbarat" - MI5.
Beirut-on-Thames, as the Palestinian writer Said Abureesh likes to call London, has since Wednesday become Beirut-on-Edge.
The writer, a former BBC Middle East correspondent, writes and broadcasts on Arab affairs.Reuse content