Moazzam Begg had written quite openly about his visits to Syria. Said visited ex prisoners & aid camps & MI5 had talked to him about trips.
"MI5 was concerned about the possibility of Britons in Syria being radicalised and returning to pose a potential threat to national security," he wrote in December 2013 on the website of his campaign group CagePrisoners.
"I told them that Britain had nothing to worry about, especially since British foreign policy, at the time, seemed in favour of the rebels. At the end of the meeting I was assured by MI5 that my proposed return to Syria to continue my work would not be hindered, and it wasn't."
Moazzem Begg writing about trips to Syria said last yr passport confiscated as police said previous trips constituted terrorism involvement.
He adds that on returning from a trip to South Africa in December he was "met upon arrival at Heathrow by officials who served me with a notice to seize my passport under the 'Royal Prerogative' stating that it was assessed my previous visits to Syria had constituted involvement in terrorism."