For safety as well as environmental reasons, the law has created a number of regulations relating to the construction and use of vehicles. Many of these relate to the manufacture of vehicles and shouldn't concern the motorist; others have to do with the condition of the vehicle.
It is important to realise that you can commit offences even if you're not aware that you've broken a rule. Therefore, if you're charged of, say, using a vehicle with faulty break lights, it's not a defence to say that you weren't aware they weren't working. You're expected to check that all is in order before setting off.
The most common offences are using a vehicle:
More information is available in the Highway Code.
The 'Vehicle Defect Rectification Scheme' (VDRS) gives the police the power to make you fix a minor vehicle defect in order to avoid a prosecution. Police use of the scheme is voluntary. Under this scheme, you must repair the defect and get the vehicle inspected by an approved garage. The result of the inspection is recorded on a form, which must be returned to the police within 14 days, otherwise you'll be prosecuted.
If the defect isn't minor, the VDRS might not be offered. In this case you're likely to be prosecuted and your vehicle could be taken away.