As a self-employed business owner you can claim the business element of the cost of running a car.
The business element is found by comparing the number of miles of business travel with the total number of miles travelled in the year.
It is recommended that you use a mileage log for your business travel, your record should include, date, purpose of journey, your start point, destination and the number of miles travelled.
Normal home to work commuting will not be classed as business travel for tax purposes.
As an alternative to claiming a suitable proportion of running costs, sole traders and business partners can instead claim fixed mileage rates for business travel in their own motor vehicle.
For cars the mileage rates are .45p per mile for the first 10,000 miles and 0.25p per mile thereafter.
The mileage rate is designed to take into account the the costs of buying, running and maintaining your vehicle, such as fuel, oil, servicing, repairs, insurance, vehicle excise duty and MOT.
The rate also covers depreciation of the vehicle i.e. it's loss in value over time.
You can't make additional claims for any of these things.
If you have claimed the cost of the vehicle through your business via capital allowances, then you can't use the mileage method and must use full cost method instead.
Any fines or penalties you incur cannot be re-claimed as a business expense.