Laptops and tablet computers are now banned from the cabins of flights from six Middle Eastern and North African countries to the UK. Simon Calder, travel correspondent (and a former security officer at Gatwick airport), tackles the key issues.

Which airports and airlines are affected?

All airports in Egypt, Jordan, Lebanon, Saudi Arabia, Tunisia and Turkey with direct flights to the UK are covered by the ban on larger electronic devices. In the case of Jordan, Lebanon and Tunisia, the only flights are from their capitals — Amman, Beirut and Tunis — to Heathrow. But from Egypt, Saudi Arabia and Turkey there are flights from multiple airports to a range of UK destinations.

The airline most affected is British Airways, which flies from all the countries except Tunisia, as well as national carriers from each of the states. From Turkey, Atlas and Pegasus are included as well as Turkish Airlines.

Other UK airlines whose passengers will be subject to the ban include easyJet, Jet2, Monarch, Thomas Cook and Thomson.

What is the new rule, and why is it being introduced?

On direct flights from any of the countries to the UK, electronic devices bigger than a mobile phone (specifically 16 x 9.3 x 1.5cm) cannot be carried in the cabin, and must be checked into the hold of the aircraft. That includes laptops, e-readers, tablet computers and some larger smartphones.

Initially the Department for Transport said: "If the device is not a large phone, laptop or tablet it is not affected by these new measures." But in the latest version of the ban, dated 28 March 2017, that policy has changed. The rules also prohibit keyboards, external hard drives and power cable transformers from travelling in the cabin. Spare batteries for these devices, or portable power sources, are banned entirely from cabin baggage and hold luggage.

First reports of the ban indicated that cameras would be banned from cabins, but they are still being allowed in carry-on luggage.

The ban is similar to a prohibition which was imposed by President Trump's administration 24 hours earlier. It appears to be based on the same basic intelligence: that bomb makers belonging to Al Qaeda in the Middle East have improved their skills and expanded their geographic spread, and are now actively recruiting would-be suicide bombers to attempt to bring down an aircraft with explosives concealed in consumer electronics.

The belief of the UK Government is that excluding anything larger than a smartphone from the cabin will reduce the risks.

How many people will it affect?

Initially, around 5,000 people per day will be on flights that meet the criteria. This will rise to 8,000-10,000 once the main summer season gets going in May.

Turkey sends more passengers to the UK than all the other countries combined.

Is this the same as the American ban?

No. The US ban, which the Department for Homeland security says is "based on the current threat picture" also covers flights from the UAE, Qatar and Morocco. The British ban does not include these countries. If it had, it would have affected tens of thousands more passengers each day. The US ban also covers larger noise-cancelling headphones.

Does the ban imply that airport security checks in the countries on the list are regarded as inadequate?

It is difficult to draw any conclusion other than that.

The UK Government is still not satisfied with security standards at Sharm el Sheikh airport, following the crash of a Metrojet plane in 2015 with the loss of 224 lives. It is believed that the Airbus to St Petersburg was destroyed by a device placed on board at Sharm el Sheikh. The airport, serving Egypt’s premier holiday resort, is still on a Foreign Office no-fly list.

How will the ban be enforced?

At overseas airports, passengers will be asked to check in any “offending” electronic devices before going through the security check. However, foreign security personnel are not being asked to enforce the ban at the main central search. A secondary search will be made at the gate, when all cabin baggage will be hand-inspected and any electronics that break the new rules will be taken away and consigned to the hold. Clearly there is no guarantee about whether, or in what condition the item(s) will turn up.

What if I have paid a hand-baggage-only fare?

The airline is likely to allow you to place items in the hold free of charge; this has been confirmed by Britain's biggest budget carrier, easyJet, which says: "We recommend that passengers do not bring large personal electronic devices if possible and would encourage customers to check in their hand baggage free of charge and bring only essential items on board the aircraft."

What if I have a connecting flight via one of the countries on the list?

The 2,000 or so travellers who each day fly in transit via Istanbul, Cairo, Beirut, Amman, Riyadh or Jeddah to the UK are generally being offered a choice. They can of course consign their devices to hold baggage at the start of the trip. Or, at least on Turkish Airlines (easily the biggest carrier), they can surrender the device at the gate for the flight to the UK. It will be placed in a special sealed case, and returned from a special desk in baggage reclaim on arrival.

What are the insurance implications?

Insurance companies generally expect travellers to keep valuable equipment with them in the aircraft cabin, rather than consigning it to the hold.

The Association of British Insurers says: “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. Some travellers may find they also have additional cover under a household contents policy for gadgets outside of the home.

"We do know some insurers already take a flexible approach to claims if a passenger has been forced to put items in the hold by circumstances out of their control.

"If devices are damaged during a flight, there’s also the potential to seek compensation through the airline.

“If travelling from destinations affected by the new regulations, it may be sensible to leave valuables at home."

What are the airlines saying?

The Government has urged airlines to take a "customer-focused approach".

Monarch says passengers from Turkey (the only country on the list from which it flies) will have their hold-baggage allowance increased by 3kg free of charge to allow for devices to be carried.

British Airways says: “If you are part-way through your journey (e.g. on a short business trip or holiday) or about to start your journey in one of these countries and feel that you are unable to immediately comply with the new UK government requirements, then we will be able to rebook your flight to a later date so that you are able to meet them. Please contact us to discuss your requirements.”

Passengers on easyJet flying from Egypt and Turkey are being advised to get to the airport three hours before their flight, "for additional security checks taking place at the gate".

Privately, airlines are concerned about what is evidently regarded as an escalated security threat, as well as the inferences the travelling public may draw on the basis of the new policy.

Does this point to wider security risks in those six countries?

No. There are already wide-ranging warnings from the Foreign Office about the nations on the list, including advice against all but essential travel to the whole of Tunisia.

How is the ban regarded by the wider aviation industry?

Alexandre de Juniac, Director General and CEO of the airlines’ organisation, IATA, slammed the rules which, he said, were launched with “no consultation and little coordination by governments”.

He demanded to know: “Why don’t the US and the UK have a common list of airports?