[Nats] were very disappointed this occurred because we have one of the best safety records in the world

Keith Williams Nats

A 28-year-old female air traffic control trainee was controlling take-offs on the runway at the time, under the supervision of a 35-year-old male mentor, the report said.

The British Midland plane was still on the runway for take-off when the British Airways plane was instructed to go round it at a late stage.

During this procedure, the BA plane performing the "go-around" was estimated to have come within 112ft of the British Midland plane.

Mentor and trainee

The crew in the British Midland plane saw the British Airways aircraft fly over and told the air traffic controller they would be submitting a report.

The mentor and trainee were relieved from duty five minutes after the incident.

The report said no criticism could be made of the trainee's performance during the near miss.

But it said her mentor, a 35-year-old man, had allowed the situation to develop to the point where the BA plane could not be "safely integrated" with the departure of the British Midland plane.

Earlier incident

When the situation became apparent, his initial actions, on taking control of the radio communications, were inappropriate, the report found.

The mentor had been selected as an on-the-job training instructor in 1999 but had said he did not particularly enjoy his job.

It was considered to have been so close to being an accident that the Air Accident Investigation Branch said we had better treat it as if it were an accident

David Learmount Flight International magazine

He had been involved in an incident in April 1999, in which he cleared a Boeing 757 to cross the runway in front of a Boeing 747.

The situation was resolved after the pilot of the departing aircraft queried his clearance.

It is understood he has now been "demoted" to a less busy airport.

Strobe lights

The system for selecting on-the-job training instructors at Heathrow was flawed at the time of the incident but has subsequently been revised, the report suggested.

The company procedure on the use of strobe lights further meant that the British Midland plane was not as visible as it could be on the runway, the report also found.

It recommended that the Civil Aviation Authority (CAA) should issue instructions requiring UK registered aircraft to use strobe lights, if fitted, when on an active runway in the UK.

Keith Williams, of National Air Traffic Services (Nats), told BBC Radio 4's Today programme: "Last year there were 460,000 aircraft movements at Heathrow and this was the only serious safety-related incident, but it is one too many.

Full investigation

"Nats were very disappointed this occurred because we have one of the best safety records in the world."

David Learmount, operations and safety editor at Flight International magazine, said: "This is a full investigation by the Air Accident Investigation Branch.

"Normally near misses are investigated - even if they are pretty serious - by the independent body known as the joint air proximity working group.

"It was considered to have been so close to being an accident that the Air Accident Investigation Branch said we had better treat it as if it were an accident."