The chilling terror attack in London last week has reminded us all of the need for sensible security measures to guard against future atrocities. While the best response to terrorism is to ensure that life goes on as normal, it is sometimes necessary to tolerate inconvenience in order to protect our safety. Air travellers have long been used to lining up for security checks and searches. Now the US and the UK have imposed sweeping bans on laptops and tablets in aircraft cabins for flights involving certain countries or airlines. The US ban applies to Middle Eastern, north African and Turkish airlines flying from 10 airports in eight countries. The British restriction covers all direct flights to the country from Turkey, Lebanon, Jordan, Egypt, Tunisia and Saudi Arabia. Other countries may follow their example.

For many passengers, laptops are considered essential items, either for working during the flight or for entertainment. No wonder affected airlines are scrambling for alternatives and ways of ensuring passengers lose their computers for as little time as possible. Whether or not the restrictions are justified depends on the content and reliability of the intelligence which prompted them. Both the UK and the US have pointed to information which suggests terrorists might use laptops to smuggle explosives. Technological experts have questioned the bans, asking why a laptop or tablet in the cabin is considered a threat and not one which is stored in the hold. The confining of the ban to certain countries and airlines also raises the possibility that it will be possible for laptops to be used for terrorist acts on carriers which are not affected. The authorities should, so far as is possible without compromising security, reveal more information so that the rationale behind the ban and the nature of intelligence concerned can be better understood.