The Civil Aviation Authority, Britain’s air safety regulator, said that portable electronic devices such as laptops and personal organisers might have to be prohibited because of the risks posed by ultra wideband (UWB).

Tests on Boeing 737 and 747 aircraft by Nasa and United Airlines in California found that UWB devices “knocked out” the collision-avoidance system, which warns the pilot of converging aircraft, and the instrument landing system that guides aircraft to runways in bad weather. UWB may also interfere with air traffic control systems that rely on satellite signals.

A ban on laptops would have severe implications for the business travel market. British Airways said yesterday that 75 per cent of its business travellers carried them. The airline is introducing a new service in February allowing passengers to use their laptops to access their workplace computer systems and use e-mail and the internet while airborne.

“It is very important for these customers to have the choice of using a laptop during a long flight,” a BA spokeswoman said. “They may need to work on a presentation or catch up with e-mails.”

The Civil Aviation Authority said that the Nasa research was not conclusive and might have exaggerated the impact of UWB by boosting the power of the devices during the tests. However, a spokesman said that either the European Joint Aviation Authorities or the US Federal Aviation Administration needed to do more safety tests to check how vulnerable aircraft systems were to UWB.

“If we obtained evidence that these devices posed a risk then we could ban them from being carried on board an aircraft. We will not allow aircraft to be endangered and there will have to be further research,” the Civil Aviation Authority spokesman said.

Existing laptops without UWB would also have to be banned because it would be very difficult to tell them apart. “The average cabin crew member does not have a degree in IT and won’t be able to judge whether a device has ultra wideband,” he said

UWB, which was developed by the military 30 years ago, allows large amounts of data to be sent short distances across a broad swath of the radio spectrum. Laptops will be able to use it to link up over short distances without cables.

It was approved for commercial development by the US telecoms regulator in February and the first devices using it could appear by the end of next year. Intel is considering incorporating UWB technology in its chips.

Passengers are already banned from using mobile phones at any time on an aircraft after research showed that they interfered with communication and navigation systems.

Laptops, CD and DVD players and electronic toys such as Gameboy must be switched off during take-off and landing because of anecdotal evidence that they cause low-level interference.

James Miller, United Airlines’ flight operations technology manager, called on federal regulators to reconsider their approval of UWB.

He told Aviation Week magazine: “Aviation is not against the promise of any new technology such as UWB. We insist, however, that any such technology meets the most stringent requirements for aviation safety.”