The Government has banned large electronic devices being carried in cabin luggage on aircraft flying into the UK from six countries.
The ban affects direct inbound flights from Turkey, Lebanon, Jordan, Egypt, Tunisia and Saudi Arabia.
The devices covered by the ban are laptops, tablets and phones which are larger than a typical smartphone, measuring 16cm by 9.3cm by 1.5cm.
These will now have to be checked into the plane's hold.
For example, an Apple iPhone 7 Plus, the firm's biggest phone, will not be affected by the ban.
The move follows the United States , which has imposed restrictions on flights originating in Cairo, Abu Dhabi, Dubai, Kuwait, Jordan, Morocco, Saudi Arabia, Doha and Istanbul.
The ban was ordered by Prime Minister Theresa May on Tuesday following a number of meetings on aviation security.
Security sources have told Sky News the move is not a reaction to a specific intelligence threat, rather a response to the ongoing general threat to aviation.
The affected airlines have been told about the order, but Number 10 said it may take a few days to fully implement the security measure.
UK airlines operating direct flights which will be affected are British Airways, easyJet, Jet2.com, Monarch, Thomas Cook and Thomson, while overseas airlines impacted are Turkish Airlines, Pegasus Airways, Atlas-Global Airlines, Middle East Airlines, EgyptAir, Royal Jordanian, Tunis Air and Saudia.
A Government spokesman said: "The safety and security of the travelling public is our highest priority.
"That is why we keep our aviation security under constant review and put in place measures we believe are necessary, effective and proportionate.
"The additional security measures may cause some disruption for passengers and flights, and we understand the frustration that will cause, but our top priority will always be to maintain the safety of British nationals.
"Decisions to make changes to our aviation security regime are never taken lightly.
"We will not hesitate to act in order to maintain the safety of the travelling public and we will work closely with our international partners to minimise any disruption these new measures may cause."
The UK has been in contact with US authorities over the issue, the PM's spokesman said.
Sky News has contacted the airlines affected by the ban.
British Airways said: "Following an announcement by the UK Government we are advising customers departing from affected airports to arrive in good time at check-in and to refer to ba.com for the latest information."
Thomas Cook said: "The new measures mean that laptops, tablets and e-readers will not be allowed in hand luggage and must be placed in the hold.
"This includes duty-free purchases of these devices in the airport. There will be no restrictions on regular-sized mobile phones, including the iPhone 7 Plus or Samsung Galaxy S7 Edge."
Monarch said: "To help our customers who are affected, Monarch will increase the paid for hold luggage allowance by 3kgs free of charge to allow for the additional weight of electrical items."
Jet2 said: "Our flights and holidays programme is continuing to operate to Turkey as normal.
"As a tour operator and airline we always follow the advice of the UK Foreign and Commonwealth Office which shows that there are no travel restrictions in place to any of our Turkish destinations.
"As always, we will do everything we can to minimise disruption for our customers, however we do recommend that customers leave extra time to allow for security processing."