Mayor of London Sadiq Khan has put a spanner in the works of those hoping for a third runway at Heathrow.
While there is a need for increased flight capacity in the south east, the clear choice is Gatwick, Khan said.
Speaking during a visit to the airport alongside its chief executive Stewart Wingate, Khan said: “Gatwick is the front door to London for millions of visitors to our city and I salute their decision to spend another £200m on improvements to the airport. They have put together a formidable plan that is a fantastic display of their confidence in London.
“The new Prime Minister has a very important decision to make regarding new airport capacity, and I urge her to rule as swiftly as possible in favour of a second runway at Gatwick, which would bring substantial economic benefits.”
Khan and Wingate hailed the £200m increase in investment, which the airport said will be spent transforming, revitalising and improving the existing airport – and will bring the total investment over the coming five years to £1.2bn.
Wingate said: “As Gatwick rapidly approaches full capacity, this increased investment paves the way for our second runway project. As we enter a new era for Britain, we must be agile and decisive as a country to show the world that we are open for business.
“It is now clear that only Gatwick can deliver the runway Britain needs to boost international competitiveness and trading links at a time when it is most needed, and we can do that before 2025.”
A Heathrow spokesperson said: “The Airports Commission disagree with Sadiq Khan and Gatwick. Following an independent, £20m, two and a half year deep-dive into the issue of airport capacity, they confirmed that Heathrow expansion could provide the capacity the UK needs more ‘easily and quickly’ than any other option.
“Brexit makes the Commission's conclusion that with Heathrow expansion, ‘the benefits are significantly greater, for business passengers, freight operators and the broader economy’, even more persuasive.”
The comments come after it was announced late last month that the airport expansion decision has been pushed back until "at least" October.
Business leaders have been pushing for a quick decision since the Davies Commission was published last July, recommended building a third runway at Heathrow.
The government said in December that it would delay making a decision on airport expansion in the south east until at least this summer, saying "more work will be done on environmental impacts" in the interim.
While many business groups would prefer to see a runway at Heathrow, they also want to see a quick decision made.
The decision may be further delayed now that Prime Minister Theresa May has appointed a new transport secretary, Chris Grayling.