MTD for VAT (already law): Since April 2019, all VAT-registered businesses must file digitally
Quarterly VAT return deadlines: usually one month + 7 days after period end
MTD for ITSA:
6 April 2026: mandatory for sole traders/landlords with income over £50,000
6 April 2027: threshold drops to £30,000
6 April 2028: threshold drops to £20,000
Income Tax quarterly updates: generally due one month after quarter ends (dates align with fiscal quarters: 6 Apr–5 Jul, 6 Jul–5 Oct, 6 Oct–5 Jan, 6 Jan–5 Apr).