Protesters against the expansion of Gatwick airport have said a new consultation on planning changes is an attempt to "sneak" a second runway through the back door.

Gatwick Airport is polling residents about changes it wants to its multi-billion pound expansion plans.

The operator wants to double capacity and create the equivalent of a second Heathrow Airport in the south east by creating a fully functioning two-runway airport capable of handling 75 million passengers a year and space for an extra 100,000 flights.

The bid is due to be examined by planning inspectors during a six-month hearing, expected to conclude in June 2024. These last minute tweaks by the airport will be submitted it says after the public has its say.

Critics however argue the changes are anything but minor and the timing of the changes could result in people who have already had taken part thinking they have played their role.

The Campaign Against Gatwick Noise Emissions (CAGNE) said: "These are not minor changes to the application for a new runway and Sussex Gatwick.  

"CAGNE feel they should consult all who have already registered an interest with the Planning Inspectorate. 

"This added consultation would appear to be a way for the airport to implement changes that could be sneaked through due to people believing that they have already passed judgement on the plans for a new runway.   

"What is proposed could see a vast increase in lorry movements by replacing an incinerator with a waste sorting plant, not included in the Development Consent Order, traffic modelling or air quality, an incinerator that at the time of obtaining planning permission was meant to heat the north terminal.  

"We do not accept that a reed bed will deal with the flooding issues that a new runway will create with significant increases in new construction field side and with a new highway and the ever-increasing heavier rainfall predictions by the Met office."

"CAGNE, the umbrella aviation community and environment group for Sussex, Surrey and Kent, has requested that they be permitted to be party to this consultation but as yet Sussex Gatwick management have not responded favourably."

The airport is proposing three separate changes.

The first is to increase the North Terminal International Departure Lounge southern extension; the second to reduce the height, and change the purpose, of the replacement Central Area Recycling Enclosure; and the third is to revise Surface Water Treatment Works.

It will be for the Planning Inspectorate to decide if the changes can be made to the application and included in the examination. The consultation will close at 11:59pm on January 21 2024.

Airport operators say expansion would create around 14,000 new jobs and inject £1 billion into the regional economy every year.

Tim Norwood, Chief Planning Officer, London Gatwick, said: "Our engagement with the public and stakeholders to date has been invaluable in helping us shape our Northern Runway plans. However, since the submission of our DCO application we have identified a number of small improvements we would like to make to our proposal.

"We are therefore asking for views on three discrete changes to our plans and would welcome any feedback people may want to make."