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HMRC internal manual

Self Assessment Manual

Interest, penalties and surcharge: interest: statutory due dates

The Statutory due dates for payment of SA liability are

Liability/charge Statutory due date
   
First payment on account  
(see note 1) 31 January before the end of the year of self assessment
  Second payment on account
(see note 1) 31 July after the year of self assessment
  Balancing payment
(see notes 1 and 2) 31 January after the year of self assessment  
  Interest Date the interest charge is created
  Penalties 30 days after the date of the notice of penalty
  Surcharge 30 days after the date of the notice of surcharge
  Revenue assessment 30 days after the assessment is made
  Determination 31 January after the year of self assessment

Notes: 

1. Statutory Due Dates (SDD) are set out in the legislation. The SDD is normally also the Relevant due date (RDD) for interest purposes. An RDD can be amended manually using function AMEND RELEVANT DATES. For information about amending a RDD see business areas ‘Amend Payment’ (SAM1000) and subject ‘Amending the Relevant Date’ (SAM60050).
   
2. When a claim to adjust payments on account is processed the due dates do not change
3. The balancing payment due date is amended if
  * There is no failure to notify chargeability, and
* HMRC issue the tax return after 31 October  

Where the balancing payment is amended the RDD for one or both payments on account for the following year is similarly amended.