A former MI5 agent has told Sky News that the agency is foiling terror "all the time" and sometimes daily.
'Tom Marcus' spent 10 years as a surveillance agent for British intelligence. Tom isn't his real name, and my interview with him was authorised by MI5.
"If we'd been briefed on a target that we needed information from, we'd go and hunt them," he said.
"We'd go and find everything we can about them, we'd watch everything they do. Essentially, as soon they come onto our grid and we need to know all information about them, our surveillance teams, myself included, would go out there and find them and make sure we control everything they do."
On another occasion, Tom was part of an MI5 team tracking a suspected Islamist terrorist. He sat outside a London mosque during evening prayers.
He said: "It was chucking it down and I was dressed as a tramp, pretending to ask for change, my own clothes soaked in my own urine to compliment that cover.
"There were more woman worshippers that had left the mosque than had gone in, so I alerted the team that there was a possibility he had changed his appearance."
The suspect had changed into a burka and was pretending to be a woman. Following him, the MI5 team called in a Special Forces unit to arrest the terrorist. Two Range Rovers slammed into the suspect's car.
