Gatwick has warned it will not build a second runway if simultaneous expansion is allowed at rival Heathrow.


The airport’s chairman Sir Roy McNulty told the Financial Times that Gatwick would also be wary if it was only allowed to expand sometime after Heathrow constructed a third runway.


Sir Roy, a former chairman of the Civil Aviation Authority, said that building a second runway costing up to £9 billion at Gatwick was a “bet the company type of investment” that would only secure an acceptable return if Heathrow was not allowed to expand.


His comments come before the Davies Commission is due to issue an interim report next Tuesday that is expected to have a shortlist of potential locations for new runways.


“We do not think we would get our money back on the investment in a new runway for at least 15 to 20 years,” said Sir Roy.


The timescale would extend to 30 to 40 years if Heathrow was allowed to build a third runway at the same time, he added.


“What businessman is going to make an investment of that nature?”


Gatwick opposes a third runway at Heathrow, and Sir Roy insisted his airport was better placed than its larger rival to support the rapid expansion of low-cost carriers on short-haul routes.


Sir Roy also claimed Heathrow’s push for more runways was undermined by the expansion of hubs in the Gulf region.


Dubai is set to overtake Heathrow as the largest airport by international passengers by 2015, primarily because it is home to Emirates, the fast-growing long-haul carrier, the FT reported.


Heathrow has stressed it will be able to compete more effectively with Dubai and rival European hubs if it has a third runway.