London City Airport says that it has untapped capacity that be put into use to help ease overcapacity in the south east.

The chief executive of LCY Declan Collier has made the suggestion after a decision on the expansion of Heathrow was postponed for more environmental tests.

The outcome won’t be known until after the London mayoral elections, infuriating businesses, environmentalists and residents – but sparing the blushes of Conservative mayoral candidate and environmental campaigner Zac Goldsmith

Mr Collier said that even if a decision had come this week, it would be a decade before the new capacity came online – whereas the Docklands hub has plans in the pipeline that could be put in place in three years.

The £200million City Airport Development Programme was approved by Labour-run Newham Borough Council earlier this year but Mayor Boris Johnson stepped in to veto the work . LCY is appealing the decision with a hearing due in the spring.

It would lift the ceiling on the number of flights from 70,000 to 111,000 a year, doubling the number of passengers by 2023 a year, as well as make major adaptations to the airport to extend the terminal and build a parallel taxi lane.

Mr Collier said: “London City Airport already has permission to operate more flights than it does today – and yet it has been prevented from doing so.

“Development at LCY does not require a new runway, or an extension to the existing runway. The airport simply needs to be allowed to make the most of what it has already got – to extend the terminal building, build additional parking stands to allow more aircraft to be on the ground at the same time, and build a parallel taxi lane, to enable aircraft to get on and off the runway quicker.

“These improvements would unlock capacity in the short term, enable the operation of more efficient, quieter next-generation aircraft, open up new markets serving the likes of the Middle East and the USA, and free up capacity for long-haul services by moving short-haul services from Heathrow.

“The Airports Commission recommended that better use should be made of existing infrastructure to mitigate the growing capacity shortage. Newham understood the benefits and decided to grant permission, the Mayor of London’s own planning officers recommended the same, but the Mayor himself acted alone to refuse the plans.”

London mayoral candidates Zac Goldsmith, left, and Labour MP Sadiq Khan at an anti-Heathrow expansion rally in October

What they say about Heathrow decision

Sadiq Khan , Labour’s candidate to be Mayor of London, said: “The Government is kicking the decision into the long grass to avoid embarrassing their mayoral candidate.

“We can’t afford more dithering over aviation capacity. Businesses desperately need more airport capacity around London, and the Tories are letting them down. Gatwick stands ready to deliver it sooner, at a lower public expense and without the damaging impact of Heathrow expansion.

“We already know Heathrow can’t be the solution. The additional damage from air and noise pollution would mean more years of delay, while protracted legal battles are fought. It must be Gatwick – and we need to get on with it.”

Conservative candidate Zac Goldsmith said: “I am absolutely delighted that, after much campaigning, the Government has heard the arguments, seen sense and will judge the options against an environmental test.

“We know that any airport expansion must meet our legally binding carbon, noise and air quality limits. There can be no doubt that in a fair contest on air quality, Heathrow will not win.

“We have a massive opportunity now to remove the threat of Heathrow expansion once and for all, and to press for an intelligent approach to London’s connectivity.

“The choice has always been between an outdated model which would lead to higher costs and less choice, or investing in a network of well connected and competing airports.”