1007-650 Summary of the current NIC rules for IR35
In summary, contractors who provide their work through personal service ‘companies’, known as ‘intermediaries’, may have to pay (or suffer, if their work is for an end-user operating in the public sector) Class 1 NICs even if they draw all their money by way of dividend. An intermediary may be not only a limited company owned by the worker but also a partnership, so even income that is nominally what is treated as trading income can be brought by the IR35 rules into income for Class 1 purposes.
The rules apply where:
•an individual ‘worker’ personally performs, or is obliged to personally perform, services for a ‘client’;