Compliance
Compliance Strategies for Self-Assessment & HMRC Deadlines Post-MTD Changes
With sweeping reforms like Making Tax Digital and penalty changes underway, UK taxpayers must sharpen compliance practices to avoid fines, misreporting or missed payments.
By NomadicTax Research Team • 5-8 min read • September 6, 2026
## Overview of Recent Compliance Reforms
- **Making Tax Digital (MTD)** for Income Tax now applies to sole traders and landlords with income over **£50,000** as of **6 April 2026**. First quarterly updates have started.([gov.uk](https://www.gov.uk/government/publications/hmrc-performance-update-april-to-june-2026/hmrc-performance-update-2026-to-2027-quarter-1?utm_source=openai))
- HMRC has opened consultations on a reform called **Timely Payments in Income Tax Self Assessment (ITSA)**, considering collecting forecasted tax liabilities via PAYE for those who also receive PAYE income, starting **April 2029**.([gov.uk](https://www.gov.uk/government/consultations/timely-payments-in-income-tax-self-assessment/timely-payments-in-income-tax-self-assessment-itsa?utm_source=openai))
- The **penalties regime** reform: for ITSA taxpayers not mandated into MTD, new rules on late submission/payment begin 6 April 2027, with easing in first year (extra days, etc.).([gov.uk](https://www.gov.uk/government/publications/budget-2025-overview-of-tax-legislation-and-rates-ootlar/budget-2025-overview-of-tax-legislation-and-rates-ootlar?utm_source=openai))
## What Taxpayers Need to Do
**1. For Self-Assessment filers**:
- Know your return deadlines: paper returns by **31 October**, online returns and balancing payments by **31 January**.([gov.uk](https://www.gov.uk/self-assessment-tax-returns/deadlines?source=post_page---------------------------&utm_source=openai))
- Payments on accounts: two instalments, due **31 January** and **31 July**. Review if expected income falls vs last year to adjust POA up/down.([gov.uk](https://www.gov.uk/self-assessment-tax-returns/deadlines?source=post_page---------------------------&utm_source=openai))
**2. Don’t ignore Simple Assessment letters (PA302)**:
- HMRC issues PA302 letters to people who need to pay tax on income not captured elsewhere (e.g. un-taxed savings interest or dividends).([gov.uk](https://www.gov.uk/government/news/hmrc-urges-customers-not-to-ignore-simple-assessment-letters?utm_source=openai))
- Deadline for payment is usually **31 January 2027** unless otherwise stated—respond early to avoid interest.([gov.uk](https://www.gov.uk/government/news/hmrc-urges-customers-not-to-ignore-simple-assessment-letters?utm_source=openai))
**3. Use HMRC tools & digital channels**:
- Pre-populated data now includes Child Benefit data for High Income Child Benefit Charge.([gov.uk](https://www.gov.uk/government/publications/hmrc-transformation-roadmap-progress-update-2026/hmrc-transformation-roadmap-update-2026?utm_source=openai))
- New digital expense service (flat rate, professional subscriptions, mileage) is being rolled out.([gov.uk](https://www.gov.uk/government/publications/hmrc-transformation-roadmap-progress-update-2026/hmrc-transformation-roadmap-update-2026?utm_source=openai))
**4. Penalties and transition periods**:
- MTD-mandated taxpayers will be subject to reporting penalties starting April 2026 onwards, but reliefs and transitional safeguards are planned.([gov.uk](https://www.gov.uk/government/publications/budget-2025-overview-of-tax-legislation-and-rates-ootlar/budget-2025-overview-of-tax-legislation-and-rates-ootlar?utm_source=openai))
- Avoid last-minute submissions; plan ahead of online filing deadlines and time-to-pay requests. Agents should remind clients of the **31 July 2026** POA deadline.([gov.uk](https://www.gov.uk/government/publications/agent-update-issue-145/issue-145-of-agent-update?utm_source=openai))
## Case Example
Mohammed is a landlord with £55,000 in gross rental income plus some freelance UK consulting under PAYE. After April 2026 he must:
- Maintain digital accounting records,
- File MTD quarterly updates,
- Consider adjusting his payments on account if rental income dips,
- Respond to any PA302 from HMRC if his interest income isn’t taxed at source,
- Avoid penalty by ensuring his return, payments and any adjustments are made before 31 January 2027.
---
**Actionable checklist**:
- If over £50,000 income: get MTD-compatible software this year.
- Estimate annual income vs last year: decide whether to apply to reduce payments on account.
- Track all income sources: dividends, rentals, interest.
- Review PA302 letters when received: check details, don’t ignore.
- Communicate with HMRC if cashflow is tight: use Time to Pay arrangements.
**Bottom line**: UK taxpayers are entering an era of more frequent reporting, larger digital interactions with HMRC, and tougher penalties—but also with more transparency and tools. Staying ahead saves you money and stress.