You can get paid a tax-free travel allowance, when you travel as part of your job.
The allowance covers your expenses for food, accommodation and necessities, it could be a cup of coffee.
You need to register your travels in a scheme. Next, your employer checks that your travel documentation contains the required information.
If your travels don't meet the requirements, or if you fail to provide information in your travel scheme, it may mean that you have to pay tax on your travel allowance for the entire year.