Passengers flying out of Heathrow’s Terminal 5 are being advised to check their travel insurance policy carefully after several firms said they would refuse to pay out if customers encountered problems with their flights or baggage.

Direct Line, Churchill and Royal Bank of Scotland (RBS) have temporarily stopped offering cover for lost luggage or delayed flights to travellers going through Terminal 5, after huge problems with baggage handling since the terminal opened.

A spokesman for RBS said that people who bought travel insurance before the problems started will still be able to make claims; but insurance bought since then may not pay out for delayed or cancelled flights, or lost or delayed luggage. He added that the situation was under "constant review" and normal cover will be restored as soon as Terminal 5's problems are resolved.

A spokesman for the Association of British Insurers said that passengers who suffer lost or delayed baggage whilst flying should always contact their airline, rather than their insurer, for compensation.

But the hardline stance has attracted criticism. Richard Mason, head of insurance at comparison site Moneysupermarket.com, said: “Lost baggage is absolutely an issue for insurers. It's pretty poor that some insurers are making new exclusions just when customers need the most protection."

Paul Wells at Norwich Union agreed that insurers are normally liable for problems with flights and baggage. He said: "Whilst the airline should be the passenger’s first port of call, if your suitcases or bags are lost, delayed or damaged, provided you have baggage cover on your policy, you should be able to claim. Just remember to report any loss to the airline immediately and get a Property Irregularity Report.

"Most standard insurance policies also provide cover if you are delayed for more than 24 hours and you choose to abandon your holiday.”

Some insurers have promised to continue to provide cover to passengers using the troubled terminal.

Lisa Harris at Saga insurance said: “The decision of some companies to introduce new exclusions for customers travelling from Terminal 5 is, in our view, an assault on common sense. Insurers that are introducing arbitrary exclusions of this nature will only encourage people to take out policies that are unlikely to meet their needs".

Mr Wells at Norwich Union said: “We are not making any changes to exclude claims from customers who travel from the terminal. We don't think it is fair to penalise customers for the problems at Heathrow as they often don't have the choice of which terminal they will fly from."