Your employer takes the tax you owe from your wages through Pay As You Earn (PAYE).
The amount you pay depends on what kind of benefits you get (external link) and their value, which your employer works out.
Check your Income Tax (external link) to see how company benefits affect the tax you pay.
Some company benefits can be tax-free (external link), like childcare and canteen meals.
You have to pay tax and National Insurance (external link) on things that are paid in cash, as they are treated as earnings.