British intelligence officers sometimes broke the Geneva Convention while interrogating terror suspects held overseas in controversial US-run prisons, MPs warned today.

UK intelligence personnel from MI6, MI5 and the Defence Intelligence Staff conducted or witnessed just over 2,000 interviews of prisoners held in Afghanistan, Guantanamo Bay and Iraq.

Tony Blair has said that information gained from the interviews in Afghanistan and Guantanamo Bay had made an important contribution to identifying and countering threats from Islamic extremist terrorist activity in the UK.

Amnesty International has complained that information obtained by alleged torture is unreliable and unacceptable.

In a report today, the parliamentary Intelligence and Security Committee said that MI6 officers were twice involved in questioning Iraqi detainees while they were hooded, in breach of the Convention.

It also found that when concerns were raised by UK intelligence officers about the treatment of prisoners by the Americans, they were not properly followed up with the US authorities.

The Committee, which oversees the work of the intelligence agencies, criticised them for failing to keep ministers properly informed about the interrogations, and about the concerns that had been raised with the US. Concerns were reported on fewer than 15 occasions.

The Committee chairman, senior Labour MP Ann Taylor, said: "We have concluded that the intelligence personnel deployed to Afghanistan, Guantanamo Bay and Iraq were not sufficiently well trained on the Geneva Convention prior to their deployment, nor did they know that the UK had prohibited certain interrogation techniques in 1972.

"As a consequence of this failure in training, MI6 officers in Iraq twice interviewed detainees who were hooded - which is a breach of UK policy."

She added: "Additionally we have concluded that the relevant ministers were not consulted before MI6 and MI5 personnel conducted interviews of detainees in Afghanistan and we recommend that they are consulted prior to such interviews.

"Ministers were also not informed in a timely way about the reports from UK intelligence personnel outlining potential abuse of detainees by the US authorities and we recommend that in future they are informed immediately."

The first incident involving the interrogation of a hooded Iraqi detainee by MI6 officers took place in June 2003. The suspect had been brought in by US guards shackled and hooded. The MI6 officers believe that these measures were for security purposes and were unaware that the hooding was unacceptable to the UK.

Times Recommends

• Michael Jackson: Not the final chapter
• Indian Army spends10m rupees on golf buggies
• Sacha Baron Cohen forced to tone down Brüno