Don't be late in paying your personal tax bill
Individual’s 2017/18 income tax, CGT, class 2 and 4 NIC liabilities should have been paid by 31 January 2019.
Note that if the balance is still unpaid at the end of February 2019 a 5% surcharge penalty is added in addition to the normal interest charge unless a time to pay arrangement has been agreed with HMRC.