Is Britain’s economic decline a victory of sorts for the country’s airport expansion foes?

The anticipated number of people wanting to fly from British airports in future has been cut substantially in official forecasts to reflect the nation’s economic decline.

Campaigners seized on the Department for Transport (DfT) figures to query the aviation industry’s claim that new airports are urgently needed to meet demand. However, the DfT said the figures meant all airports in London and the south-east would probably be operating at full capacity by 2030, though it could take until 2040 for that to happen.

The DfT said that it anticipated around 315 million passengers annually at UK airports by the end of the next decade. That is 7% fewer than predicted in late 2011 and 90 million fewer than in forecasts from four years ago. Overall, it predicts demand will grow at between 1% and 3% a year, down from a previous assumption of 5%. But its forecast range suggests numbers could double by 2050 if the building of new runways is “unconstrained”.

The latest forecast reduction is mainly due to a less optimistic assessment of the UK’s future GDP, and the related number of people able to afford air fares as the era of cheap flights ends.

John Stewart, chair of the pressure group Hacan, which represents residents under the Heathrow flight paths, said: “The exact figures about future demand may be uncertain but the trend is unmistakable: the growth in air travel in the developed world is slowing down. Any proposals for airport expansion must be seen in this light.”

The Stop Stansted Expansion group said the figures showed that even in 2050 Stansted airport could meet demand without a second runway. Residents have been alarmed by suggestions made by the London mayor, Boris Johnson that the Essex airport should be considered for redevelopment as a four-runway, 24-hour hub.

The government’s Davies commission on aviation will report in 2015 on the need for additional airport capacity in the south-east of England, with the focus likely to be on Heathrow’s thwarted plans for a third runway. Sir Howard Davies has said that one of his first tasks will be to scrutinise the official demand forecasts.