If your employer is paying you cash in hand without taking off tax and National Insurance, it’s against the law.
Some employers do this to reduce their wages bill. But if you’re working like this you won’t get the usual rights, including Jobseeker’s Allowance and sick pay.
You could also end up having to pay the tax and National Insurance back yourself, pay fines and even get a criminal record.
If you think your employer is paying you cash in hand to avoid tax and National Insurance, you can tell HMRC about it in confidence.