London - Passengers on flights to and from Britain should ensure that electronic gadgets are fully charged and can be switched on before they fly, the Department for Transport has warned.
The new guidelines come shortly after the United States boosted security measures, amid reports that terrorist groups in Syria and Yemen are working to develop bombs that are more difficult to detect.
Washington had already warned that travellers going to the US would have to be able to turn on electronic devices when asked to do so.
A spokesman for the Department for Transport said he could not comment on the routes affected for "obvious reasons.
"However, "passengers on some routes into and out of the UK may now also be required to show that electronic devices in their hand luggage are powered up or face not being allowed to bring the device onto the aircraft.
"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."