For the purposes of stamp duty land tax (SDLT), except as otherwise provided, the effective date of a land transaction is the date of completion (section 119, Finance Act 2003). The effective date may, however, be brought forward where there is substantial performance (section 44(4), Finance Act 2003). For further information, see Practice note, SDLT: substantial performance: When is the effective date?.

For the purposes of land transaction tax (LTT), except as otherwise provided, the effective date of a land transaction is the date of completion (section 71, Land Transaction Tax and Anti-avoidance of Devolved Taxes (Wales) Act 2017 (LTTA 2017)). The effective date may, however, be brought forward where there is substantial performance (section 10(4), LTTA 2017). For further information, see Practice note, Welsh LTT: substantial performance: When is the effective date?.