If you are employed and self-employed
If you are employed and self-employed, you can pay class 1 National Insurance as an employee as well class 2 and class 4 National Insurance as a self-employed person.
How much you pay is based on the normal National Insurance rules for employees and employers.
High earners (over about £40,000 or so) who are employed and self-employed may apply to defer paying some National Insurance.
There is information about this on the Gov.uk website at https://www.gov.uk/defer-self-employed-national-insurance .
Form CA72 B – used to apply to defer payment of class 2 and / or class 4 National Insurance, can be found on the Gov.uk website at – Form CA72B download page . Form CA72A – for deferring class 1 National Insurance can be accessed via the same page