If your Arrivals (purchases or imports) or Dispatches (sales or exports) of goods within the European Union (EU) are above an annually revised threshold, you must submit a Supplementary Declaration (SD). You must submit SDs if your Arrivals are above £1.5 million and/or your Dispatches £250,000 or more.
There are separate forms for Arrivals and Dispatches which can only be submitted electronically.
If you exceed the threshold on both Arrivals and Dispatches, you must separately provide information on your inbound and outbound trade and submit both forms.
The data you provide on SD forms for Intrastat purposes is also used for purposes of VAT regulations.
The threshold applies to the 12-month period from January to December. The threshold can change from year to year - any changes are normally announced in November and take effect from 1 January the following year.
At the end of the year, your obligation may change. This will depend on whether or not your EU trade for the calendar year just ending has exceeded the threshold set for the following year. If it has exceeded the new threshold, you must submit SDs throughout the following calendar year.
If you exceed the threshold during a calendar year, you must submit SDs from and including the month in which you exceed the threshold.
SDs must be submitted by the 21st day of the month following the period for which you are reporting transactions. For example, your April return must be submitted by 21 May.
It is your responsibility to monitor your EU trade to determine when you must submit an SD. HMRC will also be monitoring the value of your EU trade and may write to you from time to time to check that your records and theirs tally.