British military operations in Afghanistan will continue "substantially unchanged" after an order revising the way international troops train and mentor home-grown security forces, Defence Secretary Philip Hammond has told MPs.
Mr Hammond was summoned to the House of Commons to explain the impact of the announcement by the International Security and Assistance Force (Isaf) which will require approval from regional commanders for any joint patrols and advisory work with Afghan troops in units smaller than battalion level.
The order was issued following a spate of so-called "green-on-blue" killings of international troops by Afghan soldiers and police - or militants wearing their uniforms - as well as the upsurge of protests linked to the anti-Islam film Innocence of Muslims.
Some MPs claimed that the order amounted to a reversal of Isaf's strategy in Afghanistan, which envisages British and other international troops remaining in a combat role until the end of 2014 while training and mentoring members of the Afghan National Security Force (ANSF) to take over responsibility for security.
But Mr Hammond told the House of Commons that there was no change to British strategy and that the timetable for withdrawal remained in place.
The Isaf commander in charge of the Helmand region where most UK troops are based, US Major General Mark Gurganus, has already confirmed that he is happy for British mentoring and partnering operations to continue at below battalion level, said the Defence Secretary.
"That means that the UK partnering and mentoring operations will continue substantially unchanged by this order," Mr Hammond told MPs.
He added: "We have a strategic plan that takes us to the end of combat operations in 2014, while strengthening the ANSF to take over security responsibility from us. I have every confidence in the way COMISAF (the commander of Isaf) is executing that plan."
Mr Hammond said that the order had been decided by commanders on the ground on Afghanistan, without political input. Its effect would be to require authorisation at a higher level within Isaf for any planned joint operations below battalion level, he said.
But Conservative MP and former Army captain John Baron, whose urgent question forced Mr Hammond to come to the House, said that the new order "threatens to blow a hole in our stated exit strategy, which is heavily reliant on these joint operations continuing".