No one ever said it would be easy for British Prime Minister David Cameron – his government is an uneasy coalition, and his economic inheritance was disfigured by debt. But right now his biggest problems are coming from within. The Conservative Party is fractious; his authority has been challenged on everything from economic policy, to Europe, to his vision of progressive conservatism. Stephen Sackur speaks to veteran Conservative cabinet minister, Ken Clarke. Is Mr Cameron in danger of losing his grip?