LONDON, Oct 2, 2008 (AFP) - Britain's top policeman, Metropolitan Police chief Ian Blair, was set to resign Thursday after months of mounting pressure notably over racism charges and a mistaken killing, reports said.

Blair was expected to make a statement within the next few hours, sources quoted by Sky News television and the Press Association said.

Blair has long faced criticism over the death of Jean Charles de Menezes, an innocent Brazilian shot dead by police who mistook him for a suicide bomber in the wake of July 2005 bombings in London, which killed 56.

Then in August the Met's top Muslim officer, Assistant Commissioner Tarique Ghaffur, confirmed that he was taking Blair to an employment tribunal over alleged racism.