VIRGIN Atlantic flight VS026 from New York was coming in to land from the east on Heathrow's northern runway at 18.58 on Monday, July28, 2008. At the same time, on the southern runway, British Airways BA053 was taking off.

About 10 seconds after take-off it began to turn to its left, ie towards the north, in the usual way But VS026 failed to land,overshot, and began climbing again. This meant that the taking off BA plane was cutting across the path of the Virgin Atlantic flight, with only about 20 seconds separating them. BA053 then swung back to its right and VS 026 turned left (north) now following the path BA053 would have taken.

Eventually, VS026 completed a circle and landed 10 minutes after its first attempt, while BA053 turned towards the north again, but over Kew Gardens rather than almost immediately after take-off.

The event raises serious questions about the proposed use of mixed mode, which is the Government's preferred short-term method of increasing throughput at Heathrow.

Mixed mode envisages using both Heathrow runways for take-offs and landings simultaneously. I saw flight BA053 directly overhead when Heathrow was on easterly operations and that alerted me to something being amiss.

It is clear from events like this that the physical capacity of the airspace in the immediate vicinity of Heathrow has already been reached.

This event was dangerously close to a disaster.The idea that you can have more planes landing and taking off simultaneously is a notion that comes from people who are so driven by profit that their normal human and moral judgement has deserted them.

TOM BEATON Church Street, Isleworth.