Is your flight delayed or cancelled?

If your flight has been cancelled and you are departing from the UK or travelling to the UK with a British airline, then your airline must offer you the choice of a replacement flight at the earliest opportunity or a refund. If you are returning to Britain with a non-UK airline, you need to check the terms and conditions of your booking to see what you are entitled to.

If you choose to accept a refund, the Which? Travel editor, Rory Boland, cautions that travellers should be aware that then the airline “will have no further duty of care to you and you’ll need to make your own arrangements”. Given Heathrow is one of the UK’s busiest airports, sorting out a new flight yourself could be tricky in the short term, particularly if you are overseas.

If you are stuck in an airport you are entitled to care and assistance while you wait, which usually means refreshments, the ability to make phone calls, plus accommodation and the necessary transfers if the flight is delayed until the next day or later. If your airline tells you to make alternative travel arrangements and claim back the cost later, do not head to the nearest five-star hotel. The travel industry body Abta’s guidance is that you should incur “reasonable” costs and keep all receipts.

I am due to fly today – should I still go to the airport?

The advice is emphatically no. In a big red banner on its website Heathrow says that to “maintain the safety” of passengers and colleagues it is closed until 23.59. The airport said it expected “significant disruption over the coming days and passengers should not travel to the airport under any circumstances until the airport reopens”.

“Don’t attempt to travel to the airport,” says Boland. “Instead keep in touch with your airline for their advice.

Will I be entitled to compensation?

While airlines have a duty to look after their passengers when flights are delayed or cancelled – whether that is food and shelter or getting you on another flight – they do not have to put their hand in their pocket when disruption is caused by extraordinary circumstances.

“Compensation tends to be offered when the airline is at fault, whereas today’s event is likely to qualify as extraordinary circumstances so compensation may not be offered,” says Julia Lo Bue-Said, the chief executive of the Advantage Travel Partnership, which represents independent travel agents.

My flight is part of a package deal, can I still go away?

If your flight is delayed or cancelled and it is part of a package holiday, you have some additional protections, says Abta. If your holiday ends up being cancelled, or new arrangements are made that result in a significant change to your holiday, then your travel company must offer an alternative holiday if it can, or a refund for the full price of your package holiday. Generally, a change of more than 12 hours on a fortnight’s holiday is considered a significant change, it says.

Can I claim on my travel insurance?

Outages like this have big knock-on effects because planes and their crews are stuck in the wrong places and this morning Heathrow has already said it expects “significant disruption over the coming days”.

Simon McCulloch, the chief growth officer at the travel firm Staysure, says travellers who are unable to find a new flight within 24 hours of a cancellation may be eligible to claim on their travel insurance depending on the level of cover. “If they have travel disruption cover as part of their insurance … they may be covered for instances like this but best to check as all policies vary.” It is also worth checking your policy to see if you can recoup other expenses incurred as a result of this incident, such as car hire or airport parking fees.