If you have a damp cellar, you are very lucky. It was built to be damp. It's doing exactly what it was designed to do: Keep things cool and damp.
Back in the days when it was built, they didnt have fridges, freezers and frozen food counters in the supermarket. So when dad brought home the bacon, that's just what he did, and whopped it over a hook in the cellar, covered with a muslin bag to stay cool. He did the same with his bottles of beer, or cider. Mum would have a big bowl on the settlas which was made of pottery - glazed on the inside, like a plant pot on the outside. It stood in water, so it stayed damp, and evaporation of water from the pot kept the milk inside cool. They might have had a coal chute too, so food stored one side, coal the other. All very organised,
Nowadays, everyone wants basement damp proofing - if you have a big space downstairs that you can't use, there is pressure to make it into a room. A damp basement isn't a lot of use to anyone - if you store things down there, they get manky.
So what do you do? Well the first thing is to ventilate it. You need a good through flow of air - I'll bet it isn't at the moment. Humidity controlled extraction should make sure it stays dry. You need dry air from the house to be drawn in - so it keeps the place nice and dry. You need to make sure there aren't any modern materials on the wall - like plastic masonry paints, cement render, gypsum plaster - because they will all fall off and create the inevitable symptoms of 'rising damp'
If you REALLY can't get it dry enough like this, then you may have to go for extreme measures like using a framing system, or a commercial cavity drain system. We can investigate and advise on your options - but ventilation and opening it up are always first on our list, and inexpensive too!
In the last 10 years, Pete has not once had to tank or damp proof a cellar or basement. Always, there is a way to dry it out - inevitably using good humidity controlled ventilation. You will notice a difference in your house too - reduced levels of moisture in the basement will mean a warm dry house above it.