There is much misinformation and confusion about this issue. I am not a lawyer, or legal advisor, but I will share with you what I have learned in my research.
The first thing is - don't just ignore private parking company fines. If you receive one and you believe it has been unfairly or incorrectly issued to you, then you can follow the official appeals procedure. More about that later. But the best action to take by far, is to not get caught out in the first place! Even if you have been using the same car park for a few years, the landowner of that car park may have entered into an agreement with a private parking company at any time. So, always, when you park, check for any signs, and if you see one – read it!
There is a very important difference between public land and private land parking. On public land, the management of the land and the issuing of fines will be done by the council or the police. These fines must be paid, (unless you have a very good reason why you infringed, in which case you should appeal through official channels.) Parking bays and car parks in town or city centres are likely to be council owned and therefore on public land. Fines issued will be called a Penalty Charge Notice (PCN.)
The companies that manage car parks on private land use ANPR cameras to record your arrival and departure and if you have overstayed they will probably send you a letter with a Parking Charge Notice. These are not the same as a Penalty Charge Notice. The only way that parking companies can force you to pay these charges is by taking you to court. But they can frighten you pretty good in the meanwhile. A visitor to a well-known coffee-shop chain in Cambridgeshire who spent 20 minutes too long in the car park, received 7 increasingly threatening letters in just 11 weeks, culminating in a letter from a debt recovery agency of which the first line read “Notice of intended court action.” Even though it actually wasn't.
You should pay particular attention when using car parks at supermarkets, fast food outlets, hospitals, retail parks, rail stations, airports and motorway services, which are examples of where parking is provided on private land.
Also, you will need to approach the signs, crane your head up (they are usually placed above the average person’s line of sight and way above that of a person sitting in a car) and read what is written on the signs. Because there may be individual parking rules at each car park. Here are three types I have come across:
1) Private land car parks which have ticket machines. In some car parks, for example hotels, you can park for free if you are staying at the hotel. Otherwise you have to pay and display.
2) Private land car parks at out of town services, such as Caxton Gibbet, where there is a MacDonalds and a Costa Coffee. There are no ticket machines present. You can stay for a maximum of two hours. After that (even just a few minutes after) you may receive a £100 parking charge notice.
3) Private land car parks at suburban services, such as Costa Coffee and KFC in Eaton Socon. There are no ticket machines present. You can stay for a maximum of one hour. After that (even just a few minutes after) you may receive a £100 parking charge notice.
If you do receive a ticket or letter from a private parking company:
In a situation when most reasonable people would think a ticket is unfair, then the official advice is to appeal in the first instance to the parking company themselves. Their first letter to you notifying you of the charge will include details of their appeals system. Don’t send any money at this time. If they reject your appeal you can then go to POPLA (People On Private Land Appeals), the independent appeals service. www.popla.co.uk.
If you decide to ignore the letters, be sure to educate yourself on the level of the risk first. These websites may help: