Royal & Sunalliance's estimate for the worldwide storm bill in the last three months of 2000 has increased to £200m.
The insurer originally released a preliminary estimate in the range of £80m to £110m for losses occurring from storms and flooding in the UK and other European countries for the period October 1 to November 6.
But it has now confirmed that losses for that period were at the upper end of that range.
In addition, the company estimates that the bad weather between November 6 and the year end, primarily the flooding in the UK, but also including severe weather conditions in Canada and the continent, would incur an additional £90m to £100m.
It brings the total of fourth quarter exceptional weather-related losses to a range of £180m to £200m.
Group chief executive Bob Mendelsohn said the storms and flooding in the fourth quarter of last year should have no adverse impact on trading prospects for 2001.