Using just one mobile phone or electronic device during a flight can cause a plane’s systems to shut down, a leaked study has found.

A single Blackberry or iPad can cause the auto pilot to disengage and critical warning lights to come on, testers discovered.

The instruments which guide pilots in bad weather can also be affected by the electrical signals from such devices - with potentially catastrophic consequences.

A confidential study by the the International Air Transport Association, a trade group representing more 230 passenger and cargo airlines worldwide, found that over six years there were 75 separate incidents which caused concern.

A previous probe by the UK Civil Aviation Authority found just 35 safety alerts blamed on phones over the same time scale.