A terror suspect under a control order has escaped from a mental health unit and is on the run, the BBC has learned.
Control orders are part of the anti-terrorism effort
The man, accused by the authorities of wanting to go to Iraq to fight, has been missing for the past fortnight.
In March, the suspect, who cannot be named, became one of six British citizens to be placed under an order.
Another control order suspect is believed to have gone missing several months ago and is still at large, it has been revealed.
The first suspect escaped through a window from the mental health unit of a hospital in London two weeks ago, having been placed there under mental health laws.
After the order was imposed in March, the man initially had to report to police daily and surrender his passport. His family are concerned for his safety and are appealing for his return to fight the allegations against him.
The suspect maintains that he had been arrested during a recent visit to Pakistan, held for seven months and tortured by the intelligence services.
His brother told BBC News: "We don't know what to think. We don't know what sort of mind he might be in."
The Home Office said: "We do not comment on individual control order cases. Any breach would be investigated on a case by case basis."
Control orders were brought in for cases where there was not enough evidence for a criminal prosecution.
When placed under them, terror suspects can be tagged, confined to their homes and banned from communicating with others.
Shadow Home Secretary David Davis described the case of the suspect missing from the mental health unit as "extraordinary".
He added that it was "hard to understand how this man was allowed to escape, especially while undergoing psychiatric assessment".
Nick Clegg, for the Liberal Democrats, said the case was a "huge embarrassment" for ministers.
He said "the danger of control orders is that they short-circuit due process and keep suspects in a state of limbo".