The June and July floods that gripped parts of the UK could cost insurers between £2.25 billion ($4.55bn) and £3.25 bn ($6.58bn) in total, according to latest estimates by Risk Management Solutions (RMS), the world's leading provider of expertise, products and services for catastrophe risk management.

Insured losses from the July flood are likely to be between $2bn and $3bn, with the estimated cost of the 25 June flood ranging from $2.5bn to $3.5bn. These figures could be higher than many insurers expected, based on their initial estimates of the risk.

RMS analysis of the more than 1,000 affected postcodes shows that almost 70 percent of the areas impacted by the July floods were in areas considered to be off the major river floodplains.

"Many insurers assess their flood risk exposure based on maps that only take account of river and coastal flooding," commented Dr. Claire Souch, senior director of model management at RMS.

"The recent events highlight that these incomplete maps only provide part of the picture, and that flooding due to heavy rainfall in areas with inadequate drainage or from minor streams can have dire consequences. Those insurers that have only taken account of their risk exposure from direct river flooding could face an unexpected deluge of claims."