David Cameron, the British prime minister, has appointed a retired judge to lead an inquiry into allegations that UK spies were complicit in the torture of terrorism suspects held overseas.

The inquiry follows civil cases brought against the government by 12 ex-detainees who claim Britain colluded in their mistreatment in Pakistan, Morocco and elsewhere.

Peter Gibson, currently the intelligence services commissioner, a watchdog for Britain's security services, will lead a three-member panel investigating the claims.

British authorities say they would never use, or encourage others to use, torture to gain information.