Remember that the deadline to file your Self Assessment Tax Return is January the 31st, so not long to go!
If you have already filed your return, make sure you pay your tax bill by this date. You will have received correspondence from HMRC telling you what to pay, and on the back of that slip it will tell you the different ways to pay.
If you have not received anything, you can pay the following ways:
Direct Payment via Internet or Telephone Banking: you will need the payment amount and your reference number (this is your 10 digit UTR number), then send the payment to sort code: 10-50-41 and account number: 23456000.
By Debit or Credit Card here.
By post using the payslip that you've been sent. Make your cheques payable to 'HM Revenue & Customs' and send it to your accounts office.