All air passengers flying into or out of UK airports have been advised to make sure electronic devices in their hand luggage are charged before they travel.
The updated guidance has been issued by the Department for Transport "in line with the US advice".
A DfT spokesman said, "Passengers flying into or out of the UK are therefore advised to make sure electronic devices being carried in their hand luggage are charged before they travel."
New rules on flights mean passengers could face having electronic devices taken from them if they do not switch on.Read the full story ›
British Airways passengers who attempt to board a plane to the United States with an uncharged electronic device will not be allowed to fly, the airline has announced.
The measure follows new rules enforced in the US which stated that mobile phones, laptops, tablets and other devices without power would not be allowed onto flights in hand luggage.
In response, new British government guidelines say devices that do not switch on would not be allowed on to aircraft bound for the States.
Meanwhile British Airways has taken the extra step of telling customers that customers who bring broken or uncharged devices will have to re-book.
Uncharged phones and laptops will be barred from planes going to the US under new security measures, the US Transportation Security Administration (TSA) said.
The new rules come amid growing concern about the increased capability of al-Qaeda affiliates in Yemen and Syria, and the threat the foreign fighters of Syria pose to the home countries.
Officials in the US say some passengers at overseas airports will be asked to turn on their phones under new security measures.
The Transportation Security Administration (TSA) said it will require some foreign airports to order passengers to turn on devices such as mobile phones. Any that do not power up will not be allowed on flights to the US, and those travellers may have to undergo additional screening.
The latest security measures imposed last week followed intelligence warnings that al Qaeda's chief bomb maker, Ibrahim Hassan al-Asiri, who is thought to be based in Yemen, had linked up with jihadists in Syria to pass on his skills.
I have no doubt, from what I have learnt, that these new steps are not bureaucratic nor an overreaction.
Sadly, they are unavoidable.
It is simply foolish to believe that the threat is either minimal or now behind us.
We have, indeed, been fortunate but, sadly, this has not been because the terrorists have, since 2005, given up trying to do us harm.
As Andrew Parker, the head of MI5, has made clear, each year there have been serious plots which if they had not been identified and disrupted would have led to the deaths and mutilation of many British citizens.
Sir Malcolm Rifkind, the chairman of the Intelligence and Security Committee, who disclosed that he had been briefed in advance about the measures, said that he had been left in no doubt that they were necessary.
However, he said that he had encountered a level of complacency among some elements of the public which he found "seriously disturbing".
The head of the parliamentary committee which oversees the work of Britain's intelligence agencies has said that newly imposed airport security measures are "unavoidable".
Sir Malcolm Rifkind, the chairman of the Intelligence and Security Committee, said jihadi extremists were deploying "devilish technical skill" to create ever more sophisticated devices to evade existing security measures.
Writing in The Sunday Telegraph, he warned of the dangers of "complacency" among the public in the face of the failure of the terrorists to mount any successful mass casualty attack in the UK since the 7/7 bombings in London in 2005.
The three heads of the UK's Intelligence Agencies will make history this afternoon when they appear in public together for the first time to talk about their work.
GCHQ director Sir Iain Lobban will join Andrew Parker, the director general of the Security Service and Sir John Sawers, chief of the Secret Intelligence Service at the Intelligence and Security Committee's first open evidence session.
The televised proceedings will be subjected to a two-minute delay to prevent anything that might endanger national security or the safety of those working for the agencies being broadcast.
A criminal investigation has been launched into a contract between security firm G4S and the Government for tagging criminals.
An inquiry has been opened by the Serious Fraud Office after it emerged G4S, along with Serco, had charged the Ministry of Justice for monitoring offenders who were dead, back in prison, had their tags removed, left the country or never been tagged in the first place.
An audit by accountancy firm PricewaterhouseCoopers, launched in May, alleged that overcharging began at least as far back as the start of the current contracts in 2005.
The Government reported G4S in July when the FTSE 100 firm refused to take part in an additional audit to rule out any dishonesty.
The United Nations is to contact the United States about reports that America's National Security Agency hacked the world body's internal communications, according to the Associated Press agency.
The UN emphasised that international treaties protected its offices and all diplomatic missions from interference, spying and eavesdropping.
Its spokesman Farhan Haq said the UN would "reach out" to US officials about the reports of eavesdropping, as it has in the past when such allegations have been raised.