Thanks for your question
The company gets the capital allowance costs on the vehicle (so either 10% or 20% of the value each tax year depending on its CO2 emissions) to take into account depreciation, as well as costs of repairs, insurance and other associated costs and the employee has a P11d completed which details the car benefit charge (based on the cost of the vehicle and the CO2 emissions) as this is a benefit to the employee.
And the employer then also completes a P11db (for all company benefits on which Class1A national Insurance is due)
The main benefits clearly lies with the employee, as they have no out of pocket expenses for the car itself, but may have fuel costs (depending on whether company fuel is paid for all business mileage or not)
For the employer, other than ensuring that the employees have a reliable vehicle, and a company asset, they day to day expenses are more out of pocket, but the fact they can claim the cost of the purchase price over a number of years, means they are not out of pocket on the purchase and running of that vehicle.
Feel free to ask any follow up questions.