Eleven detainees have escaped from a British military prison in southern Iraq, the British Army has said.
The inmates escaped from a British military prison
Ten of them had "swapped" places with visitors over the past week, an Army spokesman said.
Their disappearance from the Shuaiba military base, west of the southern city of Basra, was only noticed on Friday.
A UK military spokesman confirmed that the escape plot had involved prisoners making "a change of clothes".
Major David Gell said British forces became aware of the disappearance at 1700 local time (1400 GMT).
He added: "Clearly we're very unhappy about it, it's a regrettable incident.
"An investigation was undertaken straight away and we became aware that it was a very coordinated escape involving ten people and an exchange of clothes. "
A security source told the agency that the prisoners had been held without charge for the past two years.
BBC defence correspondent Paul Wood, who is in Basra with the British Army, described it as "a very embarrassing incident" for the army.
It appeared that 10 of the detainees had swapped clothes with visitors and walked out of the prison, he said.
He added: "It does not speak of very tight security given that the British Army says these people were considered to pose a threat to the security of Iraq and to the multi-national forces."
Thousands of Iraqis are held in US and British-run prisons across Iraq for security reasons.