Experts have warned the government that a new airport in the Thames Estuary would put aircraft landing and taking off in danger of bird strikes. The last time that ministers proposed building a new hub in the south-east, a study showed that there was a significant chance that a passenger jet could be brought down after hitting one, or a flock of birds.

The report showed that even if there was substantial draining of ponds, cutting down of woodland and shooting of birds, there would still be a high risk of planes being brought out of the sky because of birds.

The original report was commissioned back in 2003 when Labour was in power and considering a new hub in Cliffe on the Kent coast. The paper is likely to cause problems as the current coalition government prepares to launch a consultation into the building of a massive new airport in the Thames Estuary.

British Air Transport Association chief executive, Simon Buck, said that bird strikes were only one of a number of concerns over the proposed plans, another being flight path conflicts with Schipol Airport in Amsterdam. He said of the Thames Gateway proposal that there were a number of technical and operational issues which needed to be tackled.

A number of major airlines, including British Airways, have said that the problem with capacity in the south-east would be better tackled by expanding existing airports such as Heathrow. However, the government has thus far ruled out adding a third runway at the hub.