19 September 2018

• CIS return date

  Construction Industry Scheme: monthly return due for period up to 5th of previous month.

• Monthly postal PAYE/class 1 NICs/student loan payment

  If you pay by cheque through the post, monthly payments due for PAYE, class 1 NICs and student loan deductions from August 2018.

21 September 2018

• EC sales list

  Deadline for online monthly or quarterly return filing.

• Intrastat

  Due date for payment of supplementary declarations for August 2018.

22 September 2018

• Monthly electronic PAYE/class 1 NICs/student loan payment

  If paying electronically, pay PAYE, class 1 NICs, student loan deductions and deductions from payments to subcontractors for the month up to the 5th of this month.

30 September 2018

• Corporation tax return

  Filing deadline for corporation tax return self-assessment form CT600 for period ended 30 September 2017 to be submitted to HMRC.

• Disclosing undeclared offshore tax liabilities

  Deadline for disclosing undeclared offshore tax liabilities (relating to income tax, capital gains tax or inheritance tax for the relevant periods) to HMRC is on or before 30 September 2018.

• CT61

  End of CT61 quarterly period.

• Company accounts filing deadline

  Deadline for filing your company tax return is 12 months after your accounting period for corporation tax ends.

01 October 2018

• Corporation tax payment

  Corporation tax payment due for year end 31 December 2017, for those companies not liable to pay their liability by instalments.