The UK’s cabin baggage ban on laptops and tablets must be implemented by Saturday, the Department for Transport (DfT) said.
It was announced on Tuesday that passengers will no longer be able to carry large electronic devices on inbound flights from Turkey, Lebanon, Jordan, Egypt, Tunisia and Saudi Arabia.
The ban covers devices larger than a typical smartphone and means that all bigger gadgets, including Kindles and other e-readers, will have to go in the luggage holds of aircraft.
A DfT spokeswoman said airlines have been told to implement the rules “over the coming days and no later than March 25”.
She added that passengers “should go to the airport with the expectation that the measures are already in effect”.
Low-cost airline easyJet said it introduced the new regime on its flights from Turkey and Egypt to the UK on Wednesday.
The move was ordered by Prime Minister Theresa May on Tuesday in the latest of a series of meetings on aviation security, although it was not immediately clear whether the move was introduced in response to a general terror threat or a specific attack from the likes of al Qaida.
It follows a similar measure announced on Tuesday by the US authorities affecting flights originating in a longer list of eight mainly Muslim countries.
UK airlines operating direct flights which are being hit by the new measures are British Airways, easyJet, Jet2.com, Monarch, Thomas Cook and Thomson.
Overseas airlines affected are Turkish Airlines, Pegasus Airways, Atlas-Global Airlines, Middle East Airlines, EgyptAir, Royal Jordanian, Tunis Air and Saudia.
Travel trade organisation Abta warned that laptops and tablets are not typically covered by travel insurance policies for loss, damage or theft if they are placed in the hold.
A spokeswoman for the organisation said: “Passengers travelling to the countries affected may wish to consider leaving their electronic devices at home, although this may be difficult for many, especially business travellers and families travelling with children.”
Mark Shepherd, of the Association of British Insurers, said: “Passengers travelling from the affected countries with laptops and tablets should check their policy and speak to their travel insurer to double-check what cover they have for valuables placed in the hold.”
He added that some travellers may have additional cover under a household contents policy for gadgets outside the home and that some insurers take a “flexible approach” to claims if a passenger has been forced to put items in the hold by circumstances out of their control.