London ? British Prime Minister Gordon Brown authorized a long-awaited inquiry into the Iraq war on Monday, but defied requests from bereaved families and campaigners to hold sessions in public.

Brown told the House of Commons that an examination of mistakes made during and after the 2003 U.S.-led invasion will begin next month, but take place entirely behind closed doors.

Campaigners have repeatedly called for a public inquiry to scrutinize what they say are a range of errors made by Britain, the United States and other allies in prewar intelligence and planning for postwar reconstruction work.

Brown said a panel of appointed experts — not lawmakers — will conduct the inquiry, led by John Chilcott, a former senior civil servant.