Willis Re said the figure only covered damaged caused in the UK. The storm has since caused extensive damage across France, the Netherlands and Scandinavia.
“Based on our research we believe insured losses in the UK for the St Jude’s Day storm to be in the region of £300m-£500m,” said Willis Re’s Tim Edwards.
“Losses from the storm were concentrated predominantly in the south of England, with significant damage coming from fallen trees – which were heavily laden with leaves because of the time of year, fallen tiles and smashed windows.”
He said overall losses were equivalent to Windstorm Kyrill, which hit the UK and caused extensive damage in January 2007.
Analysts at Oriel Securities had earlier warned that the storms were unlikely to add more than one or two percentage points to combined operating ratios – the standard measure of profitability in the insurance industry.
“UK insurers likely to be impacted are Aviva, Direct Line, esure, L&G and RSA,” said analyst Hari Sivakumaran, who pointed out that long-term forecasts had allowed ample time for precautions.