<sod >David Cameron was today due to chair a meeting of Whitehallâs civil emergencies committee, Cobra, which was expected to focus on the threat to householders along the Thames as well as the Severn.< eod>< sod > Last night David Cameron chaired a meeting of Whitehallâs civil emergencies committee, Cobra, which focussed on the threat to householders along the Thames as well as the Severn.< eod>