The Foreign Office has apologised to a senior group of MPs after a "regrettable lapse" of security procedures surrounding a planned trip to Afghanistan and Pakistan.
Details of next week's visit - which has now been halted - were sent in an unencrypted email by an embassy official in Kabul that could have been intercepted by the Taliban, the Mail on Sunday reports.
Members of the influential Commons Defence Select Committee had been due to travel to the Afghan capital, the war-torn Helmand province and the Pakistani capital Islamabad.
It is engaged in a detailed inquiry into the UK's role in the Afghan conflict
One unnamed member of the cross-party group told the newspaper they would have been "sitting ducks" if they had gone ahead with the fact-finding mission.
"We were warned that the email was not secure and that, on the advice of the spooks, we had to scrap the trip," they said.
A Foreign Office spokesman said: "We have offered an apology for this regrettable lapse in our procedures and assured the committee that we will do all we can to arrange a visit in the future."
