Britain’s interior ministry declined to confirm the news, on the principle that suspects should retain their right to anonymity.
But it stressed that the incident would be subject to an investigation.
Under the control orders, the two suspects were obliged to check-in with a police station every day and communication with others was banned.
According to the BBC, one of the men is accused of having planned to go to Iraq to fight.
He is said to be one of six Britons placed under the restrictions in March.
The man, who had to give up his passport, fled his psychiatric ward about two weeks ago.
He said repeatedly that he had been stopped in Pakistan and was
tortured there.
The second suspect has reportedly been on the run for months.
Opposition parties in Britain reacted strongly to the news, criticising the interior ministry's failure to hold the two.
Nick Clegg, the home affairs spokesman for the smaller, centre-left
opposition Liberal Democrats, said: "This should act as a spur for the
government to develop more robust ways to get suspects into court in the first place, such as using intercept evidence."