Most of the Pakistani men arrested last week in an anti-terrorist operation will be deported rather than charged, senior counter-terrorism sources told The Times.

Officials in London and Islamabad said that Britain had begun seeking assurances about how the men would be treated if they were returned to Pakistan.

“The British wanted to be reassured that if some of these men were deported they would not face torture,” an informed source in Pakistan said.

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One of the 12 men detained, an 18-year-old, has been freed from anti-terrorist detention and is in the custody of immigration officials.

Investigators are concerned that they have not found any firm evidence linking the men to terrorist attack plans. A source close to the inquiry said: “There is already talk of coming up empty-handed and there is terrible infighting between the different forces involved.”

Operation Pathway, the codename for the inquiry, has already led to the resignation of Britain’s most senior anti-terrorist officer, Bob Quick, after he accidentally revealed details of the arrest plans to photographers in Downing Street.

Click here to read more on this story from the Times of London.