For BBC journalist Alan Johnston, his time as a captive in the Gaza Strip reminds him of the adage that freedom is like air -- you only really notice it when it's gone.

"I had taken everyday freedoms of life completely for granted, as we all do, and I only really noticed their catastrophic loss when they were gone," he told CTV.ca on Wednesday.

"It's a sad thing, but I think you have to have been a prisoner of some kind, your freedom has to have been taken from you completely, for you to completely understand its importance and value and beauty."

Johnston lost his freedom on March 12, 2007 when gun-toting militants forced his car off the road and abducted him.

Abductions of foreign aid workers and journalists in the turbulent Gaza Strip are relatively commonplace. The kidnappers are usually just trying to draw attention to a grievance, and their captives are usually released unharmed within a day or two.

However, Johnston hadn't been taken by run-of-the-mill Gaza militants. He was a prisoner of the Army of Islam -- also known as the Tahwid and Jihad Brigades, and which is known to be influenced by al Qaeda.

About a year beforehand, "they took two guys from Fox News, and it wasn't some little political, domestic issue. Their agenda was global jihad," he said.

The Fox News personnel didn't get released until they had publicly converted to Islam. The Army of Islam is also believed to have been involved in the 2006 kidnapping of Israeli soldier Gilad Shalit, who is still in captivity.

"I knew that they were dangerous. They moved to another rhythm. I was scared of them, and I did everything I could to make sure I wouldn't be vulnerable to them, but Gaza's a tiny place," Johnston said.

He was 16 days away from ending his three-year posting in Gaza when the group snatched him.

At one point, they had Johnston in chains and told him they were thinking of killing him.

"There was (another) time they dressed me in a suicide bomber's jacket. I had to go on TV in their video saying if the place was stormed, I would be killed in that way," he said.

"There was definite fear that I might not get out," he said -- and there was also the fear his captivity could go on for years.

While he tried to keep his spirits up in his lightless room, depression, if not outright despair, occasionally washed over him.

A light comes on

But his captors, who didn't mistreat him for the most part, gave him the psychological equivalent of a window in the form of a radio.

"When I got the radio, amazingly, I got messages from Brian Keenan and Terry Waite," Johnston said.

Keenan had been taken hostage in Lebanon during that country's civil war in the 1980s. Keenan shared a room with fellow captive and British journalist John McCarthy. Terry Waite had come to Beirut as a peace envoy to negotiate the release of British hostages but became one himself.

Johnston said the three were those best-known to Britons as having been survivors of foreign hostage-takings.

"They were tremendously important, just to hear their voices, knowing that they had survived years," Johnston said.

"Brian Keenan said things I desperately wanted to hear at that time. He said, 'Hundreds of thousands of people are lighting a candle for you. We are waiting, and we shall not walk away.' And I paced up and down my cell, repeating that again and again and again," he said.

More than 200,000 people worldwide had signed an online petition calling for Johnston's release. Groups of journalists had held rallies in support, including in Canada and the Gaza Strip itself.

"Terry Waite said, 'You'll find more strength that you think you have, both in mind and body,'" he said.

Johnston said that proved true for him, but it's also true for anyone plunged into a traumatic nightmare, such as a parent whose child has been diagnosed with leukemia.

"Just before I was taken, a friend told me about her father. He had survived Auschwitz, and a few years later married a German woman. He seems to me to have demonstrated the best we can be -- He demonstrated our capacity to endure, to forgive and to love."

Johnston said his situation was grim, but it wasn't a Nazi death camp, a Soviet gulag or Abu Ghraib, the notorious Iraqi prison where U.S. guards degraded Iraqi prisoners.

"I felt as if I'd been buried alive, but I was waiting for a chance for my life to begin again," he said. "And amazingly, on July 4, at the darkest hour, the sun came out."

Johnston was freed and returned to Britain for a reunion with his family. He is in Canada to speak at events leading up to World Press Freedom Day on May 3.

Canadian Journalists for Free Expression has said that 102 journalists and media workers died on the job last year. Hundreds more have either been arrested or languish in jail.

Other 'captives'

Johnston notes that some Arab media colleagues have also spent extended periods in captivity -- in Western-controlled prisons.

Al-Jazeera cameraman Sami al-Haj had languished in Guantanamo Bay, the U.S. detention centre in Cuba, since late 2001. From that prison, he wrote a letter calling for Johnston's release.

"All he is asking for is a trial, a chance to answer his accusers. And that has been denied him," Johnston said. "To me, that shouldn't be."

Since Johnston spoke to CTV.ca, al-Haj has been released from Guantanamo. He was flown home Friday to Sudan where he was reunited with his wife and son. He was never formally charged with anything.

Bilal al-Hussein, an Associated Press photographer in Iraq, had been held in U.S. custody for the past two years just on the suspicion he might be a security threat. He was finally released on April 16.

The struggle between the West and radical Islamist groups like al Qaeda is one of ideas, Johnston said. "The values of the West have to be a finer thing than those put forward by the other side. And when you look at the case of Sami al-Haj, you have to ask what kind of shape are our values in?"

As for his own freedom, Johnston said if he can "hang on to two per cent of that sense of the value of freedom, I'll probably be a happier person that I would have been."

He remembered being on the airliner for Britain after his release and being stuck on the tarmac in Tel Aviv for an hour, listening to people grouse about the delay and wishing they had some perspective.

But six weeks later, "I found myself waiting for a bus in the rain and getting grumpy, and I was kind of sad that I had already arrived at the point of taking things that much for granted," Johnston said with a rueful chuckle. "But I think it was a healthy thing too. That is the nature of life."