BA jet carrying 256 passengers came within 50ft of a mystery object 'the size of four toasters' after leaving Heathrow

Air safety investigators could not identify the shiny, silver object that shot past the Boeing 777's right wing over Guildford, Surrey, on June 24. The UK Airprox Board ruled that 'providence had played a major part' and gave the incident an A-grade rating, its highest risk category. The pilot radioed air traffic control at 5,800ft, first reporting a drone. The New York-bound flight landed safely.

The pilot said the object was 'moving very fast' and 'metallic and reflective'.

A-grade incidents can be 'catastrophic', causing 'multiple deaths', the international safety scale warns.

British Airways said it takes such incidents 'extremely seriously'.