Tenants should check their building insurance to make sure they don't face crippling bills in the event of a terrorist attack.

That is the sombre warning from a leading lawyer, who points out that since the IRA campaigns of the early 1990s, insurance cover for terrorist damage amounting to more than #100,000 is available only through the Government-backed pool re-insurance scheme.

In the aftermath of September 11, warns property lawyer Ian Fisher, the availability of cover may be further restricted and the costs greatly increased, presenting landlords and tenants with difficult issues and stark choices.

While the list of insured risks in standard insurance policies includes loss or damage by aircraft - other than hostile aircraft - and devices dropped from aircraft, riot and civil commotion along with the more mundane hazards, one risk which is specifically excluded is damage caused by terrorist action.

Mr Fisher stresses that tenants need to be aware of the consequence of damage or destruction caused by a risk which has not been covered - and his warning is all the more timely in the week when New York marked the end of the recovery effort at Ground Zero, the site of the destroyed World Trade Center.

The potential costs were spelled out by fellow Charles Russell property lawyer Ian Brotherwood during a seminar during last month's Property Show 2002 at the NEC, Birmingham - and the message repeated by Mr Fisher.

"If damage or destruction arises from an uninsured risk, the tenant is responsible to make good the damage - including rebuilding the premises if necessary - even if they did not cause it," said Mr Fisher.

"Obviously, this could be extremely costly for a tenant, especially in relation to a building for which they have no long-term or capital interest.

"On top of this, the tenant would also have to pay the full rent while repairs are carried out, unless the damage was caused by events covered in the insurance policy."

Until the 1990s, damage caused by acts of terrorism was covered under the fire and explosion provisions of insurance policies, but, as a result of the substantial claims and losses suffered, the European re-insurance market refused to re-insure such risks.

This resulted in insurance companies withdrawing cover for damage by acts of terrorism by way of an exclusion in policies.

However, as the acts of September 11 and the recent resurgence of violence in Northern Ireland have shown, the need for insurance cover to protect against this is as strong as ever.