Scotland Yard was warned by MI5 its policemen were under suspicion of attending terrorist training camps it has been revealed.
As many as three policemen lost their jobs when security checks were carried out after MI5 raised concerns they may have trained as terrorists.
Rahman's lawyers say their client has never been questioned or charged under the 2006 Terrorism Act, which made it an offence to attend such training camps.
The former police officer, a Muslim who was born in Bangladesh, is the first British policeman to be publicly outed as failing counter-terrorism checks.
One of the policemen has been identified as Abdul Rahman
A source told the Sunday broadsheet: “There was concern that these people had come into the force under false pretences,” the senior Metropolitan Police source said. “There were two or three cases at the same time that were of a similar nature, where there were concerns about potential terrorist links.”
Rahman's father described his son as a "genuine and honest man" who has "nothing to hide".