THE airport company BAA has been accused of concealing the true extent of the delays faced by millions of passengers queueing for flights at its London airports by “manipulating” data.

It has also emerged that air regulators believe there will not be enough room in the skies over London for all the extra flights generated by proposed new runways at Heathrow and Stansted.

Leaked documents from the Civil Aviation Authority (CAA) and leading airlines claim that BAA distorts customer satisfaction data to conceal “disastrous” levels of service and “virtual gridlock” in some parts of its London airports.

BAA claims that it almost always meets a CAA-imposed target that 95% of passengers at Heathrow, Gatwick and Stansted should wait no more than 10 minutes to pass through security. It is fined if it fails to do so.

However, an official report to the CAA obtained by Channel 4’s Dispatches programme, to be broadcast tomorrow, says that most BAA airports have achieved this target only by not counting from the back of the queue. The report, by Booz Allen Hamilton, the business consultants, describes BAA queue measurement methods as “arbitrary” and says that “only a few [BAA] airports measure actual time spent in the queue”.

BAA’s performance was in the spotlight again last week after thousands of passengers at Heathrow could not check in their baggage because of a computer breakdown. The company has claimed that a third runway and a sixth terminal would solve Heathrow’s problems.

The plan has caused fierce opposition, with Ken Livingstone, the mayor of London, joining politicians of all parties last week to condemn it. However, the objections of the CAA and NATS, the air traffic service, could prove to be more significant.

The two bodies - which control UK aviation and airspace - say in a submission to the Competition Commission: “Were all [BAA’s] southeastern airport development plans to come to fruition, CAA and NATS are of the view that there would not be sufficient airspace to accommodate the scale of predicted growth on the basis of current and predicted technology.”

London’s airspace is already among the most crowded in Europe, with at least 20 “airprox incidents” (near-misses) in the past year. A third runway at Heathrow would add an extra 230,000 flights a year to the skies over the capital, up from 473,000 in 2006-7. Changes to flightpaths announced last week would not solve the broader capacity problem, NATS says.

On the ground, BAA has been accused of exaggerating the overcrowding at Heathrow’s terminals to make the need for a sixth terminal and third runway seem more pressing. The company is claiming that Heathrow, which handles 67m passengers a year, is an airport “designed for 45m passengers a year”. In 2006, before a third runway was proposed, BAA claimed that Heathrow was an airport “designed for 55m passengers a year”.

Further allegations of statistical manipulation against BAA are made by some of Heathrow’s leading airlines in a series of confidential letters obtained by Dispatches. Under the company’s “quality of service monitor”, a passenger survey, a new car park at terminal 3 was rated as the best in any of BAA’s London airports.

In fact, according to a letter from Virgin Atlantic, the car park is a “disaster” which is at “virtual gridlock” for much of the day. Virgin says this is an example of how BAA’s surveys are “being manipulated to distort the actual results” or are “failing to measure the real world”.

In BAA’s surveys, passengers are asked to rank facilities from 1 (very poor) to 5 (excellent). Heathrow, regularly named among the worst airports in the world in independent surveys, scored an average of 4 (good) in the BAA surveys for 2006, the worst year in its history.

Even at the height of the security meltdown caused by the “liquid bomb” plot of 2006, the BAA survey reported that passenger satisfaction with security queueing fell just 0.1 points, from 3.7 to 3.6, still close to a “good” rating.

On service quality, data collected for the current Competition Commission inquiry into BAA show further apparent discrepancies between BAA’s claimed performance statistics and the true position.

In a submission to the commission, the BMI airline accuses BAA of rigging the survey results, saying: “Our anecdotal evidence suggests that queueing times have exceeded the 10-minute standard throughout the past five years, despite the measurement process by BAA indicating otherwise.” BAA said the CAA report’s complaints about its queue measurement methods were “incorrect” and that it did measure from the back of the queue. It added that its surveys were a fair reflection of what passengers told it. “Airports around the world have adopted the same [surveying] system as us,” it said. “By any measure our performance has improved considerably in the past year.”

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