LONDON (AFP) - A passenger jet was involved in a near-miss with a drone at London Heathrow, one of the world's busiest airports, a report cited by the Sunday Times newspaper said.

The drone was involved in an incident with an Airbus A320, which can carry up to 180 passengers, on July 22 while flying at an altitude of 213 metres.

A full, official report into the incident will be published on Friday, the newspaper said, amid growing concern over the risks of shop-bought drones to commercial flights.

The incident is expected to be given an incident risk rating of A, the highest of five categories as defined by the UK Airprox Board (UKAB).

This is defined to mean there was a "serious risk of collision".

Drones are set to be one of this year's biggest-selling Christmas presents in Britain, according to electronics retailers, with some models available for as little as £30 (S$62).

The British Airline Pilots Association (BALPA), the trade union for pilots, says drones which share airspace with passenger and freight planes should be flown only by operators with training equivalent to a pilot's.

The Civil Aviation Authority (CAA), which regulates airspace in Britain, stipulates that operators of drones used for collecting data or surveillance must obtain permission before flying in a congested area or near people and property.

Other types of drones which weigh less than 20 kilogrammes are exempt from most aircraft regulations.