The ban on laptops in aircraft cabins came as the Foreign and Commonwealth Office hardened its travel advice for Egypt, Turkey, Tunisia, Saudi Arabia, Jordan and Lebanon.
“There is a heightened risk of terrorism against aviation. The threat is constantly evolving and we must respond accordingly,” the FCO said.
The indefinite additional security measures for direct flights to the UK from the six countries will be enforced from no later than Saturday.
It covers laptops, tablets and larger mobile phones which will no longer be allowed in hand baggage on inbound flights from the named countries.
Fourteen airlines are covered, including British Airways, easyJet, Monarch, Thomson Airways, Jet2 and Turkish Airlines plus seven other Turkish and Middle Eastern carriers.
Concern was raised after a “credible” tip-off to the US that Islamic State has been working on ways to smuggle explosives on to aircraft by hiding them in electronics.
Monarch responded by raising its paid for hold luggage allowance by 3kgs free of charge on flights from Turkey this summer to allow for the additional weight of electrical items.
The Department for Transportation said: “This applies to inbound flights. The UK has some of the most robust aviation security measures in the world but we keep this under constant review based on assessment of risk.
“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.”
When asked why the UK is not following the US and banning all personal electronic devices from cabins, a DoT spokesman said: “We are confident these measures are proportionate and effective.”
Transport secretary Chris Grayling said: “We understand the frustration that these measures may cause and we are working with the aviation industry to minimise any impact.
“Our top priority will always be to maintain the safety of British nationals.
“These new measures apply to flights into the UK and we are not currently advising against flying to and from those countries.”
He added that “we face a constantly evolving threat from terrorism and must respond accordingly to ensure the protection of the public against those who would do us harm.
“The update we are making to our security measures is an important part of that process.
“We remain open for business. People should continue to fly and comply with security procedures.”
British Airways warned that it is likely that passengers will be called to the boarding gate earlier in the listed countries “so please do all you can to help us depart the flight punctually”.
The airline said: “Although the UK government requirements only apply to flights from these countries, you may wish to consider how you pack your hand baggage and checked baggage on your flight from the UK so that you can comply on your return journey to London.
“All British Airways flights to/from these countries continue to operate as normal.
“If you are due to travel, please arrive in good time for the various stages of your journey including check-in, main security search areas and at the boarding gate. You will be subject to additional searches and questions.”
Monarch said that most mobile and smart phones will continue to be allowed into the cabin on its flights from Turkey.
The airline has summer services from Antalya and Dalaman, with the first affected flight from Antalya on April 29.
“We will do all we can to remind our customers about this new travel rule in our pre-departure emails and on our website and blog and will work with our partners and all parties between now and April 29 to ensure the introduction of the new measures is as smooth and secure as possible,” Monarch said.
Thomas Cook said: “The UK government has announced additional precautionary security measures for passengers on flights originating in a number of countries in the Middle East.
“The countries affected include Turkey and Egypt, so all Thomas Cook customers flying to the UK from these destinations will be impacted by the new measures.
“Please make the necessary arrangements to pack laptops, tablets and e-readers securely into hold luggage to be checked-in before going through security.”
EasyJet confirmed that new security measures on flights from Turkey and Egypt to the UK will be enforced from today.
Passengers on affected flights will not be permitted to take large personal electronics, such as Kindles, tablets and laptops into the cabin of aircraft and additional security checks will be undertaken at the gate.
“All passengers are advised to leave additional time to get to the airport and we recommend that passengers do not bring large personal electronic devices if possible,” the airline said
The safety and security of its passengers and crew is the airline’s highest priority.