Homes at risk of flooding could lose insurance cover if the Government slashes spending on new defences, Gordon Brown has been warned.

The Association of British Insurers (ABI) has urged the Chancellor to resist trying to save cash by cutting back on budgets for new flood barriers.

In a submission to the Treasury, which is carrying out a review of Government spending plans, the ABI warns such a move could lead to some homes in areas at the highest risk of flooding missing out.

Following the disastrous floods of 2000 and 2001, which had a devastating impact in Lewes and Uckfield, spending on defences was increased by ministers.

At the same time, they struck a short-term deal with the ABI to ensure policyholders would continue to get insurance cover.

The insurance companies believe properties should be protected to the extent that flooding could be expected to return not more often than once in 75 years, in order to make insuring them a viable risk.

The ABI says despite the increased expenditure, one in ten of the 1.8 million properties threatened by flooding will be in greater danger than the one in 75 year risk.

The association has told Mr Brown that it is prepared to continue covering those properties after that date if the Treasury continues its level of spending on defences, which will be £564 million in 2006.

But the expenditure is only enough to protect an extra 80,000 properties a year so it will still take at least three years to improve the barriers of the most vulnerable properties.

As a result, a cut in spending could leave more than 200,000 properties still vulnerable.