NEW government figures show that noise levels of night flights at Heathrow are almost twice the legal limit and their impact has been underestimated for almost four years.

Twickenham MP Vincent Cable is claiming the only answer is a total ban on night flights.

He said: "The greed of the airline industry for extra runways and more flights is ruining thousands of lives because of the lack of sleep night flight noise causes.

"This evidence, that night flight noise is twice the legal limit, strengthens the environmental case for a total ban on night flights.

"The Government has been lead by the nose on aviation policy by the aircraft industry. BAA and BA are setting the priorities and the Government is simply following."

Flight tests carried out for the Department for Transport since 1999 have found that the governments ratings were inaccurate.

A Boeing 747-400 was found to have twice the effect assumed in its noise rating. Most night flights involve 747-400s arriving from long-haul destinations.

Being interviewed on BBC radio, Freedom to Fly Director Dan Hodges dismissed the claims as inaccurate.

He said: "The report is inaccurate, legal night flight limits are not being broken as was reported. It is true that the noise classification of a single aircraft has been re-designated, but overall noise levels remain well within regulations."

John Stewart, chairman of HACAN ClearSkies, a pressure group for residents under the Heathrow flight path, said: "The key point is that the Government has been dishonest about the noise levels.

Protesters are on tenterhooks waiting for the final outcome of a ten-year legal battle by eight residents who were each awarded £4,000 in compensation for suffering noisy night flights.

The Government appealed and the final judgement will be given in the second week of June.

If the residents win, the Government fear they might have to pay out more than £ 2 billion in similar claims.