The UK tax system is very simple in most cases. Everyone has a “tax code” which denotes how much tax free allowance they have, if they have a company car, etc,

The UK tax system is very simple in most cases. Everyone has a “tax code” which denotes how much tax free allowance they have, if they have a company car, etc, and the tax scale is progressive with a few bands. Your employer actually deducts the tax and forwards it so as long as the code is correct (and for most regular wage earners the code is a default that is never changed) your employer’s payroll system spits out the tax withheld at the end of each month. There’s no annual return (again, for most people) and no need for refunds or additional payments. Most interest/benefits is either paid outside the tax system or already has withholding applied. I’m not saying it can never be wrong, just that the system is simple and employers have done it for years. If one really wanted to check comparing to a website like https://listentotaxman.com/m/ https://listentotaxman.com/m/ is easy. My parents have almost 100 working years between them and have never once filed a tax return. For those who do file, the return is quite straightforward. There are some weird bits — capital gains on stocks are much more complicated than the short/long hold in the US — but on the whole a UK return is a couple of dozen pages (many of which are skipped) and easily within the scope of a self-filer.