More than One Job
For income tax purposes, it doesn't matter how many jobs you have, you are only entitled to one personal allowance in any tax year. National Insurance works in a different way.
What you need to do when you start a second job
Usually, when you start a job, you give your employer a P45 document. You receive this when you leave a previous job.
If you start another job without giving up your first job you won’t have a P45. Instead your new employer will give you a P46. This form tells your new employer you are working somewhere else as well. You don't have to tell them where you are working or how much you are earning.
