MORDECHAI Vanunu's eyes glance to the side nervously as two men and a woman walk into the hotel bar where he is sitting. He leans forward and lowers his voice.

"The Israelis have said I could go back to jail for speaking to foreign journalists, " he says.

This is the man who revealed to the world that Israel was developing nuclear weapons, the man who was branded a traitor and sentenced to 18 years in prison. He was freed 11 months ago but still remains captive.

"They told me I could not leave east Jerusalem, the Arab part of the city, for 12 months or speak to foreign reporters, " he whispers.

A small, proud looking man, Vanunu looks remarkably healthy for someone who spent more than 11 years of his sentence in solitary confinement, much of it in a twometre by three-metre cell.

The sun has since browned his prison pallor.

He is wearing a dark blue jacket, Chinos, and a beige, checked shirt with a white T-shirt underneath.

A silver crucifix round his neck swings from side to side as he fidgets in his seat, stealing looks at people sitting near the bar. He summons the waiter and orders Arabic coffee.

"Mossad (the Israeli secret service) could be watching us, " he says.

Vanunu - who has been nominated for the Nobel Peace Prize every year from 1988 to 2004 - has drawn the ire of the Israeli state once again. Shortly before Christmas, detectives raided his room in the hostel of St George's Anglican Cathedral, about 100 metres along the road from where we are sitting.

They took away papers and a computer and said he was under suspicion of passing confidential material to journalists. But, despite the threat of his return to prison, Vanunu has refused to be silenced.

"I have the right to freedom of speech. Israel is supposed to be a democracy, " he says.

Eighteen years behind bars have not diluted Vanunu's beliefs or diminished his resolve to speak out against what he sees as injustices.

He still talks passionately about the fight for nuclear disarmament and how he feels he still has a part to play if or when he is finally given complete freedom.

"All states must sign up to the Nuclear Non-Proliferation Treaty, including Israel. I find it disturbing that some nations are obsessed with Iran having nuclear weapons and not Israel, " he says.

Vanunu remains in contact through the internet with peace movements around the world and has been invited to attend a conference in New York later this year to give the benefit of his experiences.

It is not so much a case of if he is eventually freed, he says, but when.

"I believe that the international pressure that has been heaped on the Israeli government since I was let out last year will continue. I am much stronger than I was 20 years ago and I will not go away. I feel vindicated and they will not grind me down, " he says. The notion of staying quiet to secure his own release does not enter the equation for Vanunu, whose anger against the Israeli state machine is clearly evident. His face is intense when he speaks and he conveys a sense of utter certainty in everything he says.

There appears to be no sense of doubt whatsoever in what he is doing.

"I want to travel and to speak about my life around the world. I would perhaps like to lecture on nuclear history and the peace movement. Maybe become an academic, " he says.

Vanunu, recently elected rector of Glasgow University, was probably among the most famous people in the world for a time.

A technician at Dimona, Israel's nuclear installation, from 1976 to 1985, he discovered that the plant was secretly producing nuclear weapons. His conscience made him speak out and in 1986 he provided the Sunday Times with facts and photos to tell the world that Israel had stockpiled up to 200 nuclear warheads.

On September 30, 1986, his tale touched on James Bond when he was lured from London to Rome by a femme fatale. There he was kidnapped, drugged and shipped to Israel and after a secret trial he was sentenced to 18 years for treason and espionage.

Famously, when he was taken to court for trial, he scrawled a message on his hand to tell the world he had been "hijacked in Rome", hoping the Italian government would demand his release. They did not and he went to prison.

Vanunu was born and raised as a Jew in Marrakesh, Morocco, before moving to Israel with his family when he was 10.

He studied at Jewish schools before doing his national service in the Israeli Defence Force. After this he became a student at the Ben Gurion University, where he studied geography, philosophy, maths and physics.

"I started to feel great sympathy for the Palestinians at this time and started an organisation to promote the interests of Jews and Palestinians together - to spread the idea of equal rights, " he says.

Despite his radical student past, Vanunu was cleared to work as a technician at Dimona in the Negev desert and it was there that he became disquieted by his discovery of a weapons programme, which is still not officially acknowledged. He took photos of the plant and smuggled them out.

The decision to put his life and freedom at risk and to leave behind family and friends was excruciating -but he believed, and still does, that it was the right path.

After contacting the Sunday Times he was flown to London for publication of his story. As the newspaper procrastinated, Vanunu met Cindy, who attracted his attention during a seemingly chance encounter in Leicester Square.

He was hopelessly smitten. "I looked at her, she looked at me, and well . . ."Vanunu says, smiling for the first time. Did he not suspect she was a spy? "No. Not at all. She never asked me anything. Her job was simply to get me to Italy, " he says.

When he accepted an invitation to go with Cindy to her sister's apartment in Rome, his fate was sealed.

No sooner had they arrived at the f lat than Vanunu was knocked unconscious, drugged and spirited to Israel on a Panamanianregistered vessel waiting off the Italian coast. "They chained me to a bed on a boat for seven days, " he says.

After his trial, Vanunu spent 11 years of his sentence in solitary confinement. There were a lot of attempts at brainwashing, he says, to get him to repent and to return to Judaism.

The authorities would even play Italian opera to deliberately irritate him as it was the country where he was captured by Mossad. Vanunu would respond by singing hymns as loudly as he could. "I used my Christianity as my defence."

His conversion to Christianity, which had happened in Australia in 1986 before he went public with the secrets, alienated his family, who live in an orthodox community in Bnei Brek, near Tel Aviv.

Vanunu's life revolves around his computer, books and walking the streets of east Jerusalem where he has become something of a celebrity. Later, we walk to his room in St George's Chapel. The court where Vanunu was tried sits yards across the road. United Nations jeeps pass by on the road and he is acknowledged a couple of times by young men. The Palestinian community in particular have warmed to him.

"I felt under threat initially when I was freed, as ultra-right-wing Jewish groups had made death threats towards me. I did not leave the church complex for about a month.

Now I have many friends, " he says.

Inside his room there are two single beds, books and a table with a computer. A calendar from Ireland hangs above his bed, showing a picture of County Mayo. Vanunu reaches beneath a table and produces a bottle of Talisker whisky from Skye, a present from Scottish friends who visited recently, he says.

There have been hundreds of letters of support from Scotland, and Vanunu hopes to visit Glasgow and Edinburgh as soon as he is free. "I was thrilled and very honoured to be elected as rector of Glasgow University. It means so much to me and I dearly want to thank the people of Scotland, " he says.

What about his future - a family perhaps? "I want to travel, I want to write my book, I want to continue my campaign against nuclear weapons and for world peace. But maybe I will meet a beautiful Scottish woman, " he says holding his glass of malt up high.

Just days after Vanunu spoke to The Herald, Israel's Justice Ministry said he was being indicted for 21 cases of violating his release restrictions and one instance of attempting to leave Israel. He now faces the possibility of a two-year prison sentence.