A MOT is a check that has to be done on your car to check that it is safe and road worthy. There is a strict criteria that the garage uses to access whether your car can pass the Mot inspection. All cars over three years old need to have a MOT carried out every 12 months and if it fails it is not allow to be driven on the road again (unless taking it to the Mot centre) until it has passed.
Unlike road tax, you do not get a reminder of when your Mot is due from the government unless the garage you bought the vehicle off or previously did the MOT sends you one off their own back.
If you are caught driving a car without an Mot not only can you get points on your license but it can also invalidate your insurance meaning that your car may be taken off the road an you have to pay recovery and storage charges to get it back.