At present the self-employed pay two types of national insurance:
A fixed weekly rate(class 2) if your profits are above about £6,000 and
A rate on profits(class 4) if your profits are above about £8,000
It is planned that from April 2018 the class 2 contributions will be dropped, leaving just class 4 payable.
Although total class 2 contributions only amount to less than £150 per year, this will be a welcome reduction and simplification of the system.
The class 4 contributions are also planned to be revised so that they will then count towards benefit entitlement, such as the state pension.