LONDON (Reuters) ? Leading insurers have vowed to pay out where possible to policyholders caught up in Thursday?s fatal bomb attacks in London, despite many of their policies carrying terrorism exclusions.

More than 50 people were killed and 700 wounded in the four blasts on the London underground and a bus on Thursday.

Three of the four biggest health and critical illness insurance providers ? Axa, Standard Life and Norwich Union ? said on Friday they would pay out under their critical illness, income protection or accident, sickness and unemployment policies.

?Subject to the normal excess limits that apply, we are not going to enforce any terrorist exclusions in light of yesterday?s events,? said Norwich Union spokeswoman Lorna Wiltshire.

?We are not expecting many claims in respect of PMI (medical insurance) policies as many of the injured are being treated in accident and emergency units. However, our cover includes psychiatry and physiotherapy for example, which some people might need as part of their recovery process,?Wiltshire said.

Axa said it would cover any follow-up care needed by any of its policyholders injured in the blasts, subject to the normal pre-approval process. Standard Life said despite a general terrorism exclusion, policyholders would be covered for the attacks.

Some personal travel insurance policies have explicit terrorism cover such as Norwich Union, Axa, Marks & Spencer and the Post Office. Other companies such as Churchill, Endsleigh and Direct Line that don?t offer terrorism cover could still be sympathetic to individuals who have been injured.

Churchill Insurance said: ?We will provide cancellation and personal accident cover if customers are physically injured on the way to their holiday departure. ... If any of our customers are away on holiday and hear of injury or death to a close relative, we will facilitate their return home.?