"The Bahraini government says we are working with Iran," Mr al-Arab says as he leads me down an alley beyond the mosque. He is a diminutive man with a pointed Spanish Armada beard who pushes his key into the front door of a cramped apartment of flaking yellow paint. "There - this is my home. Does it look as if we are supported by Iran?"
Mr al-Arab is the local representative of the Islamic Front for the Liberation of Bahrain, the strongest if not the largest of Bahrain's opposition groups which was accused - wrongly, according to the Front's spokesmen - of planting last week's bomb outside the Diplomat hotel in the Bahraini capital, Manama. His young wife Khatoun sits beside her husband in a black chador, lowering her eyes as a series of men enter the room with its oil stove and faded furnishings.
Many of the men are bearded, most are members of the front and all speak of Sheikh Issa bin Salman al-Khalifa and his government with suppressed fury. Each of them has been imprisoned and deported from the island, on the orders - so they all insist - of Ian Henderson, the British head of Bahrain's intelligence services.
When Sayed Hisham al-Moussawi walks into the apartment, the other men nod gravely. He is an immense figure, perhaps 7ft tall, his black leather jacket and military-style camouflage trousers strangely at odds with his almost snow-white hair.
"What do you expect me to think of the al-Khalifas?" he asked. "I have been imprisoned in Kuwait for my opposition activities and then in Bahrain. I was tortured in Bahrain, molested by an officer; a Jordanian officer working for Henderson beat my wife in front of me. There are a number of people who do the beatings in the al-Qalaa prison and the intelligence headquarters. One is called Mohamed Ouweyed, another is Mohamed Hijazi. There is a Pakistani who is very hard - Aziz Sugager. But the Jordanian colonel, he is the worst."
Mr Moussawi, described by Amnesty International as a political prisoner after he was jailed in 1988 for allegedly conspiring to overthrow the government, spent five years behind bars. He was deported in April 1993, with a newly issued Bahraini passport, valid for just one year. The moment he mentions this, the other men produce their own equally worthless passports.
One deportee has been given only a laissez-passer, others have discovered that instead of Bahraini nationality, their new identity documents describe them only as "residents", thus potentially depriving them of citizenship. Mr Moussawi, holding passport number 721773, described how he was forcibly deported to Syria on 30 April 1993 on Gulf Air flight GF 901. "I told the pilot that I refused to leave my home, that I didn't want to go to Damascus," he said. "But he said he would have to take me. Is that allowed under international law? The pilot was British."
Into the room walks Sheikh Abdullah Salih, his baby daughter in his arms. He was first arrested in 1980, he said, for demanding a return to parliamentary democracy. "I was hung upside down and beaten with fists by four men," he says.
Sheikh Salih fled Bahrain 13 years ago because he feared arrest - plain-clothes police called at his home three days' later. He travelled to India, to Saudi Arabia and then to Tehran where he says he studied theology for five years. Was this only religious studies, I asked? And the Sheikh noted my scepticism. "I went only for my courses," he replied.
So was there any Islamic Front office in Tehran? Mr al-Arab denied this. But he added that the front maintained a "representative" in Iran, something which I didn't doubt. Funds came from "our own people" and from their families in Bahrain.
"We want a proper democracy in Bahrain," Mr al-Arab said. "The other [opposition] groups want the return of the 1973-75 parliament and the 1972 constitution. But we want a full democracy with a completely elected parliament, not the one we had before where ministers were automatically given 14 of the seats. And we want a constitution that forbids the Emir to dissolve parliament."
Mr Moussawi rose to leave. "I don't think there is a solution in sight in Bahrain," he said with resignation. "But we believe in God and we will win, even it takes a long time."
There wasn't much doubt why Sheikh Issa's government regards the Islamic Front as its principal enemy.
Ian Henderson, the secretive Briton who runs Bahrain's brutal intelligence services, now plays a critical role in the island's future, negotiating between Shia opponents of the Bahrain government and the island's ministers. In the Independent on Sunday tomorrow, Robert Fisk profiles the hero of Britain's war in Kenya who turned into one of the most feared secret policemen in the Gulf.Reuse content