Government to Implement MTD for IT With Lower £20,000 Threshold: What the Phase-3 Mandate Means for UK Landlords

From 6 April 2028, landlords and self-employed taxpayers with qualifying income above £20,000 will be mandated into Making Tax Digital for Income Tax (MTD ITSA) under the phase 3 threshold confirmed at Spring Statement 2025 and Autumn Statement 2025. Phase 3 is the largest of the three phases by population. HMRC's published impact assessment estimates roughly 700,000 to 800,000 newly-mandated taxpayers at the £20,000 level, dwarfing the phase 1 (£50,000 from 6 April 2026) and phase 2 (£30,000 from 6 April 2027) cohorts combined.

For a landlord identifying as phase 3 in scope, the 18 to 24 months from today to the 6 April 2028 mandate start are the planning runway. The decisions made in that window (software choice, voluntary opt-in pilot, accountant engagement via Agent Services Account, joint-property arithmetic with spouse, incorporation review) determine whether the mandate transition is operationally smooth or whether the first quarterly deadline arrives in chaos.

This page is the phase 3 announcement landing page. We set out what the £20,000 threshold catches (and what it does not), how the gross-test trap works for landlords with high gross and low net, how joint-property arithmetic and Form 17 elections interact with the phase entry, the cross-stream qualifying-income aggregation effect that pulls landlords with side income into scope, the accelerated Schedule 56 late-payment penalty regime that applies to MTD ITSA filers from 6 April 2026 onwards, and the planning runway for a landlord with the 6 April 2028 start date already on the horizon.

The three-phase MTD ITSA mandate timeline

The mandate framework sits at Schedule A1 of the Finance (No. 2) Act 2017 and is operative under the Income Tax (Digital Obligations) Regulations 2026 (SI 2026/336), which revoked the earlier Income Tax (Digital Requirements) Regulations 2021 (SI 2021/1076) on 1 April 2026. Substantive mechanics carry over; the regulation numbers have migrated (qualifying income at reg 25, qualifying amount at reg 27, three-year income-exit at reg 24). The three phases:

• Phase 1: mandate from 6 April 2026 for qualifying income above £50,000. Determining return: 2024/25 SA return. Newly-mandated cohort estimated at around 130,000 landlords and self-employed taxpayers.
• Phase 2: mandate from 6 April 2027 for qualifying income above £30,000. Determining return: 2025/26 SA return. Newly-mandated cohort estimated at around 200,000.
• Phase 3: mandate from 6 April 2028 for qualifying income above £20,000. Determining return: 2026/27 SA return. Newly-mandated cohort estimated at 700,000 to 800,000.

Phase 3 is the structural majority of the MTD ITSA programme. The earlier phases bring the largest landlords and the most professionalised operators into scope; phase 3 brings the long tail of mid-tier landlords, accidental landlords, and small self-employed operators who run sub-£20,000-net but cross the gross-test threshold.

The 2026/27 determining return: when phase 3 status is set

HMRC tests phase 3 eligibility against the qualifying-income figure on the 2026/27 SA return, filed in the ordinary course by 31 January 2028. The notice of MTD ITSA mandate goes out from HMRC in the months following that filing, ahead of the 6 April 2028 start.

The determining-return mechanic has two practical consequences. First, a landlord who expects to cross the threshold in 2026/27 should treat the SA return for that year as the trigger document. Second, a landlord whose 2026/27 income is borderline (close to £20,000) should review the gross-rental computation carefully before filing; an over-stated gross by a few hundred pounds can push the landlord into scope unnecessarily, and an under-stated gross (where the landlord under-reports for a different reason) can leave them out of scope on paper but in scope on the true facts.

Qualifying income: the gross-test definition

Qualifying income for MTD ITSA threshold testing is the sum of gross self-employment income PLUS gross property rental income, measured BEFORE any deductions. The two streams are aggregated; deductible costs are not subtracted before the threshold test.

The gross-test architecture is the most operationally important feature of the threshold. Many landlords assume the test is at net profit level (where their actual taxable income sits well below £20,000) and discover at the determining-return stage that the gross figure pulls them into scope. The standard misalignments:

• High-mortgage BTL portfolios: gross rental £22,000, mortgage interest £14,000, agent fees and repairs £4,000, net profit £4,000. Gross test puts the landlord in scope; net profit suggests they should not be.
• Serviced-accommodation operators: gross rental £25,000, cleaning + utilities + platform fees £12,000, net profit £13,000. Gross test in scope; net profit suggests phase 3 borderline.
• Mixed rental and self-employment: £15,000 gross rental + £8,000 gross self-employment = £23,000 total qualifying income, above the £20,000 phase 3 threshold even where neither stream alone would be.

The discipline for a landlord planning toward phase 3 is to model gross-rental figures forward from 2026/27 onwards. A property let at £1,200 per calendar month generates £14,400 gross annual rental. Two such properties take a landlord above the £20,000 phase 3 threshold even before any self-employment side income is layered on.

Joint-property arithmetic under section 19.4

For jointly-owned property, each owner tests against their share of gross rental, not the property's total gross. The default spouse-split is 50/50 absent a Form 17 election. Form 17 elections (made under the Income Tax Act 2007 architecture, with TCGA 1992 consequences for the underlying ownership) can bring one spouse into scope earlier than the other.

Default 50/50 split

Mr and Mrs Tasburgh own 2 jointly-held BTL properties with combined gross rental £40,000 per year. Default 50/50 split puts each spouse at £20,000 qualifying income. The "above £20,000" wording in the operative regulations puts each spouse just BELOW the phase 3 cliff on these facts: neither is mandated. A small uplift in gross rental in any future year (to £40,001 combined, £20,000.50 per spouse) flips both spouses into scope simultaneously.

Form 17 election with uneven split

Mr and Mrs Pewsey have the same £40,000 combined gross rental but made a Form 17 election in 2022 to split 75/25 in Mr Pewsey's favour. The mechanics:

• Mr Pewsey: 75% × £40,000 = £30,000 qualifying income. At phase 2 threshold (above £30,000 from 6 April 2027), so he is in scope from the 2027/28 tax year onwards.
• Mrs Pewsey: 25% × £40,000 = £10,000 qualifying income. Below phase 3 threshold (£20,000), so she is not in scope at any phase on current facts.

The two spouses face very different planning runways from the same jointly-owned property: Mr Pewsey must enter MTD ITSA from 6 April 2027 with full quarterly plus EoPS plus final declaration discipline; Mrs Pewsey continues in regular self-assessment indefinitely.

Worked example: bridge-population landlord at £22,000 gross

Mr Crowborough owns 2 BTL flats; gross rental income £22,000 per year; mortgage interest plus agent fees plus repairs leave £8,000 net profit. No other qualifying income.

Threshold testing:

• Phase 1 (above £50,000): £22,000 gross is below. NOT in scope from 2026/27.
• Phase 2 (above £30,000): £22,000 gross is below. NOT in scope from 2027/28.
• Phase 3 (above £20,000): £22,000 gross is above. IN SCOPE from 6 April 2028 (2028/29 tax year onwards).

The 2026/27 SA return (filed by 31 January 2028) is the determining return. Mr Crowborough must check his 2026/27 qualifying income against £20,000; if it exceeds, HMRC issues the mandate notice ahead of the 6 April 2028 start.

Planning runway:

• Q4 2026 to Q2 2027: choose MTD-recognised software from the gov.uk Find Software list.
• Q2 to Q3 2027: optionally opt in voluntarily for the 2027/28 tax year to pilot the operational workflow before mandate bites.
• Q3 2027: if engaging an accountant, set up the Agent Services Account (ASA) authorisation. The legacy 64-8 paper authorisation does not work for MTD ITSA.
• 6 April 2028: mandated. Four quarterly updates per business stream plus EoPS plus final declaration.

Worked example: the gross-test trap with low net profit

Mrs Tunbridge owns 1 BTL property; gross rental £22,000 per year. Mortgage interest £14,000 plus agent fees £1,800 plus repairs £2,200 plus insurance £600 = total deductible costs £18,600. Net profit only £3,400.

Qualifying income is the GROSS figure £22,000, before deductions. Above £20,000 phase 3 threshold means Mrs Tunbridge is IN SCOPE from 6 April 2028 despite her tiny net profit. Many landlords in Mrs Tunbridge's position assume the threshold is on net profit (where £3,400 is safely below £20,000). The gross-test cliff catches a meaningful slice of the £20,000 to £50,000 bracket where mortgage interest restriction and other deductible costs leave net profit very low.

The operational impact: Mrs Tunbridge's quarterly cycle from 6 April 2028 onwards requires reporting gross rental and allowable deductions four times a year. The compliance overhead is the same as for a landlord with £30,000 net profit; the underlying tax liability is much smaller. The proportional cost of MTD ITSA compliance is much higher at the bottom of the phase 3 cohort than at the top.

Worked example: cross-stream aggregation puts a small landlord in scope

Mr Ashford owns 1 BTL flat; gross rental £15,000 per year. He also runs a small self-employed bookkeeping practice with gross self-employment income £8,000 per year.

Threshold testing: qualifying income = £8,000 self-employment + £15,000 rental = £23,000. Above £20,000 phase 3 threshold means Mr Ashford is IN SCOPE from 6 April 2028.

Counter-example: Mr Ashford's neighbour Mr Brackley has £18,000 gross rental and zero other qualifying income. Total £18,000. Below £20,000 means Mr Brackley is NOT in scope at any phase on current facts.

The two operators have very similar property positions but very different MTD outcomes. Side income that the landlord may treat as informal or hobbyist (online sales, freelance work, consultancy) counts for qualifying-income purposes if it is reportable self-employment income. Landlords with side income should aggregate at the gross level, not the net level, and not assume that small side income is below the radar.

The MTD ITSA quarterly cycle

Once mandated, a phase 3 filer faces five obligations per tax year per business stream:

• Quarterly update 1: covering 6 April to 5 July, due 7 August.
• Quarterly update 2: covering 6 July to 5 October, due 7 November.
• Quarterly update 3: covering 6 October to 5 January, due 7 February.
• Quarterly update 4: covering 6 January to 5 April, due 7 May.
• End of Period Statement and final declaration: due 31 January following the tax year end.

A calendar-quarter election is available for landlords who prefer quarterly periods aligned to the calendar (1 January to 31 March, 1 April to 30 June, 1 July to 30 September, 1 October to 31 December). The election is made annually and is operationally helpful for landlords whose accounting records are already organised on a calendar-quarter basis.

For a landlord with both rental and self-employment, each business stream files its own four quarterly updates and its own EoPS. The final declaration is consolidated across all streams at year end. A landlord with one rental property and one self-employment activity files 8 quarterly updates plus 2 EoPSs plus 1 final declaration = 11 obligations per year. The compliance overhead is significantly higher than the legacy annual SA return cycle.

The penalty regime: points-based late filing and accelerated late payment

Late filing: Schedule 55 FA 2009 points-based regime

Each missed quarterly update or EoPS earns 1 point under the Schedule 55 points framework as amended for MTD. Reaching the threshold (4 points for a quarterly filer; lower for less-frequent filers) triggers a financial penalty of £200. Subsequent missed submissions each attract a further £200 financial penalty until the points are reset by a continuous in-compliance period.

The points-based architecture is less punitive for a single isolated missed submission than the legacy Schedule 55 £100 immediate penalty; it is more punitive for sustained patterns of late filing because the £200 financial penalty bites repeatedly until the in-compliance period restores the points to zero.

Late payment: accelerated Schedule 56 schedule

The Schedule 56 late-payment schedule applies in an accelerated form to MTD ITSA filers from 6 April 2026 onwards (alongside the corresponding VAT MTD acceleration):

• From day 15: 3% of unpaid tax.
• From day 30: a further 3% of unpaid tax (cumulative 6%).
• From day 31: 10% per annum, charged daily, on the unpaid balance.

The legacy 5% / 5% / 5% Schedule 56 schedule continues to apply to non-MTD self-assessment filers. The acceleration is a real shift in the late-payment cost profile for MTD ITSA filers and changes the cash-flow calculation around delaying tax payments to manage liquidity. A landlord who could absorb the legacy 5% penalty at the 30-day mark may find the 6% combined penalty plus 10% per annum daily accrual materially more expensive.

Software readiness path

The MTD ITSA software market has matured significantly in the 2024 to 2026 window. HMRC maintains the recognised-software list at the gov.uk "Find software for Making Tax Digital for Income Tax" page; the list updates periodically as new products gain recognition. The recognised options fall into three categories:

• Full-stack accounting software: products that handle bookkeeping, MTD quarterly submissions, EoPS, and final declaration in a single integrated workflow. Suited to landlords who want everything in one place.
• MTD-specific filing apps: products focused on the MTD submission layer, designed to sit alongside a separate bookkeeping system or spreadsheet.
• Spreadsheet-plus-bridging: a spreadsheet (Excel, Google Sheets) used as the underlying bookkeeping record plus an HMRC-recognised bridging tool that submits the data to the MTD ITSA service. Acceptable provided digital-link discipline is maintained throughout (no manual re-keying between the spreadsheet and the bridging tool).

For a phase 3 landlord choosing software in 2026 or 2027, the recommendation is to wait until closer to the 6 April 2028 mandate (around Q2 2027 for a software review) rather than locking in a product 18 months ahead. The recognised-software list will continue to evolve; pricing models and integration depth will shift; and the operational fluency of the software vendors will improve as phase 1 and phase 2 cohorts pilot the workflow.

Agent representation: the ASA flow

For landlords using an accountant, the authorisation route differs by filing mode. Self-assessment supports both the legacy 64-8 paper authorisation and the Agent Services Account (ASA). MTD ITSA supports ASA only: the legacy 64-8 does not authorise an agent for MTD ITSA quarterly or final-declaration submissions.

The implications:

• Landlords with an existing accountant on 64-8: the accountant must be moved onto the ASA flow before the mandate start. The transition is operationally simple (the agent initiates the ASA authorisation and the client confirms via Government Gateway) but cannot be left to the first quarterly deadline.
• Landlords appointing a new accountant for MTD ITSA: the agent must use ASA from the outset. Any "I will sort the agent authorisation later" approach will fail at the first quarterly cycle.
• Landlords changing accountants mid-cycle: ASA authorisations do not transfer between agents. The outgoing agent's authorisation is revoked and the incoming agent's authorisation is set up afresh. The discipline is to avoid mid-cycle changes where possible.

The exit path under section 19.5

A taxpayer in MTD ITSA can exit if qualifying income falls below the relevant threshold for three consecutive tax years. The exit is a positive notification to HMRC; without notification the taxpayer remains in MTD ITSA notwithstanding falling income.

The three-consecutive-year buffer is deliberate. It prevents in-and-out cycling around the threshold, which would create administrative churn for both HMRC and the taxpayer (each cycle would require fresh software setup, fresh ASA authorisation, fresh quarterly-cycle re-orientation). The buffer also means that a landlord whose income dips temporarily (one-off vacant period, major refurbishment cycle, COVID-style market disruption) continues to file MTD quarterly through the dip.

Re-entry into MTD ITSA after exit is automatic if income subsequently rises above the threshold. The same determining-return mechanic applies: the SA return for the year-2-before-mandate sets the eligibility test for re-entry. A landlord who exited at the end of 2031/32 and whose 2033/34 SA return shows qualifying income back above the threshold would be re-mandated from 6 April 2035.

The LtdCo question: does incorporation take me out of MTD ITSA?

Yes. Limited companies are outside MTD ITSA. They file CT600 annually under the corporation tax regime, with the 12-month CT600 filing deadline under Schedule 18 FA 1998 and the 9-months-1-day CT payment deadline under TMA 1970 section 59D (or quarterly instalments for large companies above the £1.5 million augmented-profits threshold, subject to the associated-companies divisor).

For some landlords, incorporation is an attractive route out of MTD ITSA compliance overhead. For others, the cost of incorporation outweighs the saving:

• SDLT on transfer: properties transferred from individual to LtdCo attract SDLT at market value, with the 5% additional-property surcharge plus residential rates (the surcharge was raised from 3% to 5% on 31 October 2024 by FA(No.2) 2024). For a £400,000 BTL portfolio, SDLT on incorporation is around £30,000.
• CGT on transfer: the disposal from individual to LtdCo is a market-value disposal for CGT purposes, with chargeable gains crystallising. Incorporation relief under TCGA 1992 section 162 can defer the gain in narrow circumstances (where the property business meets the trade test, which is rare for passive BTL portfolios).
• Ongoing CT compliance: the CT600 cycle plus statutory accounts plus confirmation statement plus PAYE for director salary plus dividend documentation is a meaningful compliance overhead, although it is annual rather than quarterly.
• Dividend extraction: profits taken out of the LtdCo as dividends attract income tax at 8.75% / 33.75% / 39.35% (basic / higher / additional rates), on top of the 19% / 25% CT layer.

For a landlord with phase 3 exposure but a long-term hold strategy and rising profits, the incorporation route may net out positively over a 10-year horizon. For a landlord with a single BTL or a short-term holding plan, the SDLT and CGT cost of incorporation typically outweighs the MTD ITSA saving. Specialist advice on the full incorporation comparison is essential before treating MTD ITSA as the driver of incorporation.

The planning runway from today to 6 April 2028

For a landlord identified as phase 3 in scope, the planning runway from today to mandate start is around 18 to 24 months. A structured approach:

1. Q4 2026 to Q1 2027: compute the expected 2026/27 qualifying income. Where the figure is close to the £20,000 threshold, review the gross-rental computation carefully. Consider whether the gross is genuinely above or below the cliff.
2. Q1 to Q3 2027: review software options on the gov.uk Find Software list. Shortlist 2 to 3 products that match the landlord's complexity (single BTL, multi-property portfolio, mixed rental and self-employment).
3. Q2 to Q3 2027: optionally opt in voluntarily to MTD ITSA from 6 April 2027 to pilot the workflow before mandate. The voluntary opt-in route is available at gov.uk/guidance/sign-up-as-an-individual-for-making-tax-digital-for-income-tax.
4. Q3 to Q4 2027: if using an accountant, set up the Agent Services Account authorisation. Confirm the agent's ASA capability and software compatibility.
5. Q4 2027 to Q1 2028: reconcile joint-property arithmetic and Form 17 status with the joint owner. File any deferred Form 17 election ahead of the 2026/27 SA return.
6. Q1 to Q2 2028: file the 2026/27 SA return. Confirm the qualifying-income figure and receive the HMRC mandate notice. Finalise software setup.
7. 6 April 2028: mandate start. First quarterly update due 7 August 2028 covering 6 April to 5 July 2028.

The phase 3 cohort is large and HMRC's processing of mandate notices around January to April 2028 will be busy. Landlords who leave software setup, ASA authorisation, or joint-property arithmetic to that window will face a steep first-cycle ramp.

If your property income sits in the £20,000 to £50,000 gross-rental bracket and you would like a steer on whether you are in scope, how the gross-test arithmetic falls out on your specific facts, and what the planning runway looks like for your circumstances, we work with landlords on the MTD ITSA mandate transition from determining-return review through software selection, ASA setup, and first-cycle operational support.