VATTOS5105 | Actual tax points: payments: introduction
From HM Revenue & Customs · VAT Time of supply
Under the normal time of supply rules the receipt of a payment in advance of the basic tax point will always create a tax point. Payment is also generally one of the tax point triggers that feature in the special rules provided by the time of supply regulations. It should be noted that a payment for a supply covered by the normal time of supply rules does not create a tax point where it is received after the basic tax point has occurred.