No, he didn't. He joined a terror group falsely claiming to be Islamic. He is not Muslim, nor are any of the terrorists or terror groups.
It was while at Feltham that Mr Reid is said to have converted to Islam.After his release, he followed the path taken by many other Muslim prisoners, to Brixton Mosque, in south London.
The place of worship has a reputation for attracting converts and helping ex-offenders re-adjust to life in the outside world.
Initially he fitted in well. Taking the name Abdel Rahim, he became known for his willingness to get involved in the workings of the mosque and to learn Arabic.
But at some point Mr Reid began to get involved with extremist elements, says the chairman of Brixton Mosque, Abdul Haqq Baker.
Mr Reid was "tempted away" by "individuals who set up a few years ago away from the mosque", Mr Baker says.
"Their teachings were a lot more militant."