A judge-led inquiry is to be held into claims British security services were complicit in the torture of terror suspects, the BBC understands.

Prime Minister David Cameron is to announce the inquiry is being set up, possibly as early as Wednesday.

In opposition the Conservatives and Lib Dems called for an inquiry into claims by UK resident Binyam Mohamed British agents were aware of his torture.

The former Labour government insisted the UK did not use or condone torture.

The security services have always denied allegations they were complicit in torture.