The corruption charges which earned Asif Ali Zardari, the Pakistani president, the nickname "Mr Ten Percent" are coming back to haunt him. The country's top court has struck down an amnesty that allowed Zardari to return to Pakistan and protected him. As president, he still has immunity from prosecution, but his opponents say the ruling makes him ineligible for the presidency. It could also reopen cases against thousands of other officials, including cabinet ministers loyal to Zardari. Imran Khan reports from Islamabad, the capital.