Britain last night took the dramatic step of banning laptops from the cabins of UK-bound flights from six countries, amid fears terrorists have perfected a new type of airline bomb.

The move, which is likely to spark travel chaos at affected airports, was imposed just hours after a similar ban was unveiled by the United States.

It comes amid fears that Islamic State, al Qaeda and other terror groups have developed the capability to hide a bomb in a laptop big enough to blow a hole in the side of a plane.

As Britain bans electronic devices in cabins of flights from SIX countries, we explain what you can bring - and what to do with the things you can't

The ban, which will be phased in over the coming days, will affect travellers on direct flights to the UK from the popular holiday destination of Turkey, two north African countries – Egypt and Tunisia – and three Middle Eastern states: Lebanon, Jordan, and Saudi Arabia.

Passengers will be banned from taking large electronic devices into the aircraft cabin, such as laptops, iPads, Kindles and Nintendo 3DS game consoles. Portable DVD players will also be banned.

The move, which is the biggest clampdown on airline security since the 2006 liquids ban, was ordered by Theresa May yesterday following talks with security officials. It follows weeks of discussions with the US security agencies about the growing threat of a laptop bomb.

The PM’s official spokesman declined to comment on the precise reason for the clampdown, but added: ‘The safety and security of the travelling public are our highest priority.’ In February last year a bomb concealed in a laptop blew a hole in the side of an aircraft in Somalia.

But some security experts questioned the effectiveness of the rules. Labour said it was seeking ‘urgent clarification’ of the thinking behind the restrictions. And the Liberal Democrats questioned why the UK was following President Trump in targeting majority Muslim countries.

The ban is expected to cause chaos as airlines and passengers struggle with the new rules.

Last night it was unclear what will happen to passengers who arrive at the gate with banned devices. Travellers who would otherwise have carried only hand luggage will be forced to pay extra fees for a checked bag if they want to use their gadgets at their destination.

Transport Secretary Chris Grayling acknowledged that the restrictions would lead to ‘frustration’ for passengers, but said officials were working with airlines to ‘minimise any impact’. Travel trade organisation Abta warned that laptops and tablets are not typically covered by travel insurance policies for loss, damage or theft in the hold.

Air industry consultant John Strickland warned that the ban will cause ‘headaches for airlines and customers’ but said carriers had ‘no choice but to put security first’. He added: ‘One unexpected consequence will be the challenge of additional devices with lithium batteries being stowed in the holds, which brings its own challenges to safety.’

The ban applies to flights from Turkey, two north African countries – Egypt and Tunisia – and three Middle Eastern states: Lebanon, Jordan, and Saudi Arabia. Stock image

Government sources flatly denied that the decision to follow the US so quickly was designed to cosy up to Donald Trump and give succour to his controversial travel ban on Muslim majority countries. They declined to comment on why other EU countries have yet to impose similar curbs.

A former GCHQ officer said: ‘Jihadists can get hold of Semtex and C4 and store this in the laptop and get through the X-ray system. A suicide bomber would then sit by the window, and he would only need a small charge to blast the window to devastating effect.’

Asked why the US ban, which affects ten named airports in eight countries, differs from that imposed by the UK, the PM’s spokesman said ministers were confident the UK plans were ‘effective and proportionate’.

But Shashank Joshi, of security think-tank the Royal United Services Institute, said: ‘It is unclear why only some airlines and countries are affected, given that a potential attacker can easily re-route their journey.

‘Without clarification, this risks being seen as a form of pointless “security theatre” which causes great disruption with little benefit to aviation security.’

Why is it safer to put laptops in the hold?

What’s happening?

Passengers flying from Turkey, Lebanon, Egypt, Saudi Arabia, Jordan and Tunisia to the UK have been banned from taking their laptops and other large electronic devices into the cabin. Instead they will have to check in these devices so they are stowed in the baggage hold. The ban applies to any electric devices larger than 16cm by 9.3cm by 1.5cm (6.3in by 3.6in by 0.6in) and includes iPads, oversized smartphones, DVD players, Kindles and small games consoles.

When does it start?

No official start date for the ban has been set as airlines will need time to implement the changes. But the Department for Transport says anyone flying from one of these locations must be prepared for it to be enforced immediately.

Does it just apply to direct flights?

No, it also applies to transfer flights. In other words, those travelling into the UK via one of the banned countries – and those travelling from a banned country via the UK to another destination.

Why is this happening?

The decision follows a similar ban by Donald Trump’s administration. The US ban – which comes into force from Saturday afternoon – applies to ten airports in eight countries, also including Qatar and Kuwait. The US said it was concerned about recent attempts by terrorist groups to circumvent airport security and detonate bombs on planes – including the downing of a plane in Egypt in 2015 – and the armed attacks against airports in Brussels and Istanbul last year. US officials cited the failed attempt to down a plane in Somalia last year when a laptop containing a bomb was passed to a passenger after they had gone through security.

Why these countries?

Those included in the UK ban – all of which have large Muslim populations – are deemed to pose a high terrorist threat. The Government refused to explain why it did not follow the US example and extend the ban to Kuwait and Qatar.

Why is it safer to stow a laptop in the hold?

Security sources say that if a bomb is taken into the cabin, it takes only a minor explosion to blow out a window and bring the plane down. An explosion in the luggage hold is likely to be less catastrophic. It is also much harder for a terrorist to detonate the bomb if it is in the hold. At most airports passengers are told to take out their laptops and electronic devices from hand luggage when they go through security. But terrorists have still found ways to smuggle laptops containing explosive devices through security, without being detected by X-ray scanners.

How many flights are affected?

The Department for Transport said it could not disclose this for security reasons. But it is thought fewer than 200 flights a day travel from these six countries to the UK. Six UK airlines – British Airways, EasyJet, Jet2.com, Monarch, Thomas Cook and Thomson – will be affected, and eight overseas airlines: Turkish Airlines, Pegasus Airways, Atlas-Global Airlines, Middle East Airlines, Egyptair, Royal Jordanian, Tunis Air and Saudia.

How will the ban work?

This is where it becomes more sketchy. The Department for Transport has left it up to the airlines. Government officials have advised passengers who plan to travel to the UK from these countries to check with their airline, and to check the size of their devices. Travellers using check-in desks will be advised whether they need to stow their devices in the hold. Airlines are likely to arm staff with perspex letterbox-style tools to ensure devices do not exceed the size limit. There will also need to be secondary checks at the departure gate for passengers who checked in online. This is where the ban is likely to cause the most trouble – because these passengers will have only hand luggage and will be told they cannot take large devices on board.

What if my electronic device is too big?

This again depends on the airlines, but they appear to have been caught off-guard. BA last night said its flights would continue to operate as normal but urged passengers to check-in in good time and monitor its website for updates.

Should I cancel my flights to these countries?

No. The Department for Transport says it is not advising against flying to these countries. But it has urged those with imminent travel plans to contact their airline for more information.

How long will the ban last?

No timeframe has been given. But – as with the US – the ban is unlikely to be lifted until the threat recedes.

Will I have to pay extra to check a bag in?

Passengers could face extra costs if they want to take these types of devices away with them. Many travellers hoping to save money by choosing hand luggage-only fares now face extra baggage fees.

Will my gadgets still be insured?

Passengers should contact their insurer before putting expensive devices in checked baggage.