The force is working with Horsham District Council and West Sussex County Council Trading Standards to investigate five companies suspected of operating illegally, officers said.
A spokesman for Sussex Police said the businesses claim to offer secure, reliable and affordable parking for people accessing the airport.
On Wednesday, June 22, officers and members of both councils visited the field where they discovered hundreds of keys to the vehicles in the boot of a car which was left open and unlocked. Several other vehicles were covered in mud.
In addition, some keys were left in envelopes on the windscreens of the cars they belonged to, in full view of anyone passing by.
The location of the field is not being released to protect customers’ vehicles, the spokesman added.
Officers are urging drivers to beware of rogue traders and only book with approved parking companies, pending the investigation.
Sergeant Darren Taylor said: “We visited the site with the district council and trading standards with the aim of exposing and taking firm action against these unscrupulous rogue companies.
“I was disgusted but not overly surprised by the condition of the cars, because this appears to be an ongoing issue in the area. Some of the cars were stuck in thick mud and were unable to be towed away; let alone driven away.
“But one of the most worrying things we found was an insecure vehicle with the keys to hundreds of others left in full view in the boot. We were on site for about 45 minutes and not a single person was present to challenge us during that time. There was nothing stopping us from accessing the field and no CCTV cameras anywhere in sight, which is a real concern.
“Clearly, what is being advertised by these companies and what is actually happening are two completely different things, and we’d like to make people aware of this. The simplest advice we can give is to look on the Gatwick Airport website for approved parking operators, and not opt for a company just because it is the cheapest. The chances are, if something seems too good to be true, it probably is.
“From a policing point of view, we will be looking at all the drivers associated with the companies and if there is any evidence of any criminal activity, we will act upon it accordingly.”
You can report issues by visiting www.westsussex.gov.uk/tsreport or by calling Citizens Advice on 03454 040506.
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