European investigators looking into claims of secret CIA prisons will release an interim report today saying US agents illegally transported and held terrorist suspects on the continent, the leader of the inquiry says.

Detainees at Guantanamo Bay, Cuba, including one brought up in Britain, have told a human rights group they were tortured at a US-run secret prison in Afghanistan.

Prisoners in US custody in Afghanistan suffer “systemic” mistreatment, Human Rights Watch said today, calling for a network of secretive jails dogged by allegations of assault and sexual abuse to be opened to outside scrutiny.