A British Airways jumbo jet carrying 400 passengers to Hong Kong was forced to take evasive action in what aviation experts have called one of the closest mid-air near-misses on record. The plane came within seconds of colliding with a Korean Air freighter while flying at 10,000 metres over the mainland on June 28 before the pilot forced the plane into a dive. Passengers were unaware of how close they had come to a possible disaster, although one woman was knocked from her feet as the plane changed course. The incident happened when BA027 was flying at about 880km/h at the cruising altitude assigned by mainland air traffic controllers four hours before it was due to land. Warning systems in the cockpit alerted the British pilot, Captain Gerry Girard, that a Korean Air 747 was emerging from the clouds below just 200 metres away at a closing speed of 1,600km/h. 'Essentially the pilot got the warning signal from the traffic control and alert system on board and saw the aircraft approaching at the same time,' a spokesman for British Airways said. 'He is one of our most experienced check pilots and took immediate action to ensure the safety of the passengers and aircraft and was able to basically duck under the approaching Korean aircraft.' The incident is being investigated by mainland authorities as well as the British Civil Aviation Authority and both airlines. A spokesman for the British side confirmed a full investigation was taking place into an 'air proximity incident' but refused to give any further details. But sources close to the investigation said the Korean aircraft, carrying freight from Seoul to Uzbekistan, had apparently been climbing from its assigned cruising level 700 metres below the scheduled British Airways flight from Heathrow to Chek Lap Kok. It is understood the Korean aircraft's on-board warning systems led the pilot to believe another plane was approaching and the pilot thought he was taking evasive action. 'I would certainly agree this is one of the closest British incidents and it could well be one of the closest near-misses ever to have taken place anywhere in the world,' a source said. The British Airways 747-400 continued on to Chek Lap Kok, where tests determined its warning systems were working.