If you received a tax assessment with a balance to pay notice and it has not paid in full by the deadline, then you will be charged for late payment. You will have 10% added to the amount of tax that remains unpaid.
The late payment surcharge will not be applied if:
Late payment notices are issued shortly after the deadline date.
Probably a good idea to therefore double check your liability against the payments that you have made in order to not fall foul of the 10% surcharge!