Making Tax Digital for Income Tax Self Assessment (MTD for ITSA) represents the most comprehensive statutory reform of UK personal taxation since the introduction of Self Assessment in 1996. Authorized under Section 60 of the Finance (No. 2) Act 2017 and codified in Section 12CC of the Taxes Management Act 1970, MTD for ITSA replaces the annual retrospective tax return with digital record-keeping and regular quarterly digital submissions.
Understanding your statutory obligations requires reviewing the phased mandation schedule, the quarterly submission timetable, and HMRC's strict digital link requirements.
The Phased Mandation Timeline & Gross Income Thresholds
Unlike the previous annual Self Assessment rules which focused on net taxable profits, MTD for ITSA mandation is determined strictly by gross qualifying income (total trading turnover plus gross rental receipts, before deducting any business expenses):
| Mandation Date | Statutory Threshold | Population in Scope |
|---|---|---|
| 6 April 2026 | Exceeding £50,000 | Sole traders and landlords whose combined gross business turnover and property receipts exceed £50,000 |
| 6 April 2027 | Exceeding £30,000 | Sole traders and landlords whose combined gross income exceeds £30,000 |
| Under Review | Under £30,000 | Businesses under £30,000 remain outside mandatory scope pending government review |
How HMRC Tests Chargeability
HMRC assesses your chargeability using the information on your prior tax returns. For example, your 2024/25 Self Assessment return (submitted by 31 January 2026) dictates whether you must comply with MTD from 6 April 2026.
Exemptions: Trustees, personal representatives, non-resident companies, and individuals eligible for digital exclusion (due to age, disability, or lack of internet connectivity) are exempt from MTD for ITSA.
The New Filing Rhythm: 4 Quarterly Updates + Final Declaration
Under MTD for ITSA, taxpayers no longer file a single annual SA100. Instead, you operate under a five-stage reporting cycle:
1. The Four Quarterly Updates
Taxpayers must submit a summary of business income and expenses every three months using compatible software. Updates can follow standard tax year quarters or calendar quarters:
- Quarter 1 (6 Apr – 5 Jul): Due by 7 August
- Quarter 2 (6 Jul – 5 Oct): Due by 7 November
- Quarter 3 (6 Oct – 5 Jan): Due by 7 February
- Quarter 4 (6 Jan – 5 Apr): Due by 7 May
Note on Cumulative Submissions: HMRC allows quarterly updates to be submitted cumulatively. If an expense from Quarter 1 is discovered in Quarter 2, it can be included in the Quarter 2 submission without amending the earlier quarter.
2. The Final Declaration (Replacing the SA100)
By 31 January following the end of the tax year, taxpayers must complete the Final Declaration (the EOPS / Finalisation process). This step incorporates:
- Non-business income (PAYE employment, dividends, bank interest, capital gains).
- Statutory tax reliefs, personal allowances, and accounting adjustments.
- Confirmation that the information submitted across the year is complete and correct.
Digital Record-Keeping & The "Digital Links" Rule
Under the statutory regulations, retaining paper receipts or manually copy-pasting numbers into HMRC's web portal is illegal under MTD:
- Digital Recording: Every business transaction (sales, invoices, purchases) must be recorded digitally in compatible software near the time of transaction.
- Digital Links: Data transfer between software programs must be digital (API connection, automated file import, or automated data formulas). Manual re-keying or copying and pasting is strictly prohibited under HMRC notice.
The New Points-Based Penalty Regime
To enforce regular filing, Schedule 24 to the Finance Act 2021 introduced a points-based penalty regime replacing automatic £100 fines:
- Each missed quarterly deadline accrues 1 penalty point.
- For quarterly filers, the penalty threshold is 4 points.
- Once 4 points are reached, an immediate £200 penalty is issued.
- Every subsequent missed deadline triggers an additional £200 fine.
- Points expire only after a clean period of statutory compliance (12 months of on-time quarterly submissions) and once all returns for the past 24 months have been submitted.
How ac-co Delivers Complete MTD ITSA Compliance
ac-co is engineered from the ground up as a native HMRC MTD-compatible software suite:
- Connects directly to UK bank accounts via Open Banking, creating legally compliant digital audit records in real time.
- Compiles quarterly updates automatically and submits via HMRC's Making Tax Digital API with a single review.
- Tracks your cumulative gross turnover against the £50,000 and £30,000 thresholds.
- Prepares and files your Final Declaration by 31 January, ensuring complete continuity with past Self Assessment history.