The decline is similar to the performances in July and August and comes six months after traffic across its seven airports slumped by 11.3%.

Heathrow saw a marginal fall of 0.3% to 5.8m passengers in September, but a 5% decline in aircraft movements meant the load factor on planes – the proportion of seats occupied – rose to 78.2% from 73.9% a year earlier.

BAA said strong demand on long-haul routes to India and the Middle East drove the performance.

Gatwick’s passenger numbers were down by 0.5%, but this represented the airport’s best performance since May, 2008.