Making Tax Digital (MTD) is HMRC’s initiative to digitise the UK’s tax system, making it easier for taxpayers to manage their obligations while reducing administrative errors. It requires businesses and individuals to keep digital records and submit updates using compatible software, rather than relying on paper-based methods.
MTD is therefore part of the UK government’s effort to create a more modern, digital-first tax system. It shifts the work of tax reporting from manual processes to digital tools, where records are stored electronically and submissions are made via software that connects directly to HMRC’s systems.
The core idea is to automate much of the tax process, helping to close the “tax gap” caused by errors or underreporting. It’s not a new tax but a change in how existing taxes are handled.
While it promises efficiency gains, some evidence suggests mixed results in practice, with benefits like fewer errors not always realised for all users. MTD has been rolled out in phases, starting with VAT, and plans for Income Tax are underway, but Corporation Tax extensions were canceled in 2025.
Find out more from https://sovos.com/vat/tax-rules/uk-making-tax-digital/
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HMRC Paper Tax Return Processing: A Stage-by-Stage Guide
Think of HMRC’s paper tax return processing like a factory assembly line where each document passes through multiple quality control checkpoints. Each stage has specific legal requirements, timings, and potential bottlenecks. Here’s how it works:
STAGE 1: Receipt and Logging
What Happens
Returns arrive at HMRC and are first logged into the Local Data Capture (LDC) system – a separate computer system specifically for processing returns.
Legal Basis
Section 8 & 8A TMA 1970: Returns must provide “information reasonably required for the purpose of establishing the amounts in which a person is chargeable”
Key Infrastructure Limitation
LDC operates independently – it cannot access the main computer system during logging and capture. This is like having a sorting facility that can’t see the main warehouse inventory while sorting packages.
Delays Can Occur From:
High volume periods (October deadline creates bottlenecks)
Returns arriving without proper identification
Physical damage to documents requiring special handling
STAGE 2: Initial Assessment & Triage
What Happens
Returns are assessed for quality and completeness. They’re categorized as either:
“Process Now” – Straightforward returns that can be processed quickly
or – Requiring Repairs – Returns needing corrections before full processing
Legal Authority for Repairs
Section 9A TMA 1970 permits HMRC to repair “obvious errors and mistakes” within 9 months of receiving the return
Unsatisfactory returns requiring correspondence with taxpayers before processing
Complex cases needing manual review
Returns with more than 10 repairs (requiring separate letters instead of automated processing)
STAGE 3: Data Capture & Entry
What Happens
Return information is entered into the LDC system through the CAPTURE RETURN function. This is manual data entry by HMRC staff.
Infrastructure Limitations
This is a significant bottleneck – think of it as transcribing handwritten documents into a computer, one box at a time. Unlike online returns that arrive digitally, paper returns require:
Manual reading of handwriting
Interpretation of figures
Entry into multiple data fields
Delays Can Occur From:
Illegible handwriting requiring clarification
Volume surges after October 31st deadline
Staff availability – limited number of operators with necessary user roles
Complex returns with multiple supplementary pages taking longer to process
Partnership returns requiring additional Standard Accounts Information (SAI) capture
STAGE 4: Revenue Calculation (If Requested)
What Happens
If the taxpayer requested HMRC to calculate their tax (rather than doing it themselves), HMRC performs this calculation.
Legal Obligation & Critical Timing
For returns submitted by 31 October following the tax year end, HMRC is obliged to calculate the tax.
However: If submitted late, HMRC will still calculate on request “but cannot promise to do so before 31 January” following the end of the SA year.
This is a critical policy limitation – like a restaurant warning they can’t guarantee service times for late orders.
What’s Generated
Tax Calculation (SA302)
Revision Notice (if repairs made) – detailing corrections and reasons
Customer Service Messages (maximum 10) – advice on return completion
Delays Can Occur From:
Late submission after October 31st
Returns requiring extensive repairs
Cases needing more than 10 repair/customer service messages (requiring separate correspondence)
STAGE 5: Posting to Main Computer System
What Happens
Information captured in LDC is transferred to the main computer system and “posted” (recorded) to the taxpayer’s permanent record.
Legal Implications
Once posted:
Self-assessment becomes official
Payment obligations crystallize
Interest calculation begins on late payments
The enquiry window opens – HMRC has 12 months from receipt date to open compliance enquiries
Infrastructure Issue
This is a batch process, not real-time. There’s a time lag between capture and posting, similar to how banks process transactions overnight rather than instantly.
Delays Can Occur From:
System processing cycles
Validation errors requiring manual intervention
Need to coordinate with other systems (PAYE, payments)
STAGE 6: Generation & Issue of Tax Calculation
What Happens
HMRC sends the taxpayer:
Tax calculation showing liability
Revision Notice (if repairs made)
Statement showing account position
Timing Constraints
For returns submitted:
By 30 September (pre-2007-08) or 31 October (2007-08 onwards): Calculation issued with time to pay by 31 January
After these dates: Calculation issued but may not arrive before 31 January payment deadline
Policy Rationale
The October deadline exists to ensure taxpayers receive calculations with sufficient time to arrange payment before the 31 January deadline – giving them roughly 3 months’ notice.
Delays Can Occur From:
High volumes after October deadline
Cases requiring special handling (more than 10 repairs)
Postal delays
STAGE 7: Enquiry Window & Compliance Period
What Happens
After posting, HMRC has a 12-month enquiry window starting from the date the return was received.
Legal Framework
For 2007-08 onwards: 12 months from date return received
For 2006-07 and earlier: 12 months from filing date, or until the quarter date following the first anniversary if filed late
Why This Matters
HMRC can make amendments during this period under Section 9A TMA 1970. After the window closes, changes require:
Returns received just before the enquiry window deadline
Cases selected for compliance checks
Requests for additional information
Key Infrastructural Limitations Throughout:
Dual System Architecture: LDC operates separately from the main computer, requiring data transfer between systems
Manual Processing Dependency: Unlike online returns, paper requires human data entry
Batch Processing: Updates happen in cycles, not real-time
Volume Sensitivity: October 31st deadline creates processing bottlenecks
Limited Automation: Maximum of 10 repair/customer service messages can be automated; more require manual letters
User Role Requirements: Only staff with specific user roles can process returns, limiting flexibility
Critical Policy & Legal Timeframes:
Event
Deadline
Legal Basis
Consequence of Missing
Paper return filing
31 October
Section 8 TMA 1970
£100 penalty
HMRC calculation guarantee
31 October submission
Revenue obligation
No guaranteed calculation before 31 January
Payment due
31 January
Section 59B TMA 1970
Interest charges, penalties
Repair window
9 months from receipt
Section 9A TMA 1970
Cannot make simple corrections
Enquiry window
12 months from receipt
Section 9A TMA 1970
Limited ability to challenge return
The entire process reflects a tension between thorough manual checking (ensuring accuracy and preventing errors) and processing speed (meeting statutory deadlines). The infrastructure limitations mean that late submissions create a cascading effect – like traffic congestion where each delayed vehicle slows down all those behind it.
Here’s a clear, practical walkthrough of how to set up a Time to Pay (TTP) arrangement with HMRC and what it means for your Self Assessment liability
Time to Pay (TTP) — What It Is
A Time to Pay arrangement lets you spread your Self Assessment tax bill over affordable monthly instalments if you can’t pay it in full by the deadline.
It’s not automatic — you must apply, but HMRC routinely agrees if:
You have a good compliance history,
The tax debt is temporary (e.g., cash flow issues), and
You show that you can keep up with the new payment plan.
Example: Your Case
You owe £1,500 (balancing payment) for 2024/25, due 31 January 2026. You can’t pay the full amount but could manage £250/month.
You can ask HMRC for a 6-month Time to Pay plan from February to July 2026.
How to Apply
Online (fastest)
If your circumstances are straightforward, you can do it online:
Basic info about your income, outgoings, and savings
HMRC will assess affordability and agree a reasonable plan.
How It Affects Interest & Penalties
Type
What happens under TTP
Interest
Continues to accrue until the debt is cleared, at the usual HMRC rate (e.g., 7.75%)
Late payment penalties
Paused once the arrangement is agreed and you stick to it
New penalties
None added as long as you keep up payments
Defaulting
If you miss a payment, HMRC can cancel the plan and restart penalties
Example Outcome
You agree to pay £1,500 in 6 instalments of £250 starting 28 Feb 2026. Interest over 6 months at 7.75% ≈ £44.
Total payable = £1,544 spread over 6 months.
As long as you:
Make each payment on time, and
File future returns and payments promptly,
No late payment penalties are applied.
Tips for a Successful Plan
Offer to pay something upfront (even 10–20%) — HMRC views this positively.
Be realistic — it’s better to propose a smaller, sustainable amount than to miss a payment.
If your income changes, you can amend the plan by contacting HMRC early.
Keep a record of every conversation or confirmation email.
How HMRC calculates the interest during a Time to Pay plan (with the month-by-month breakdown)
Let’s walk through a month-by-month example showing how HMRC calculates interest under a Time to Pay (TTP) arrangement for your Self Assessment balance
Example: Interest During a Time to Pay Arrangement
Scenario
Item
Details
Tax owed
£1,500 (2024/25 balancing payment)
Due date
31 January 2026
TTP agreed
6 monthly instalments of £250 starting 28 February 2026
HMRC interest rate
7.75% per year (Bank of England base + 2.5%)
⚙️ How HMRC Works It Out
Interest is charged daily on the remaining unpaid balance.
Each time you make a payment, the outstanding balance drops, and daily interest thereafter is calculated on the reduced amount.
The formula HMRC uses is: [ \text{Interest} = \text{Balance} × \text{Rate} × \frac{\text{Days outstanding}}{365} ]
Here’s a numerical example showing how HMRC calculates your expected liability under Self Assessment
Example: Calculating Expected Liability
Background
Your total tax and Class 4 National Insurance liability for 2023/24 (after PAYE and other credits) = £12,000.
You are self-employed and still trading in 2024/25, so HMRC assumes your next year’s liability will be roughly the same.
Step 1 – Work out the payments on account
Expected liability for 2024/25 is based on 100% of the previous year’s liability, split into two instalments:
[£12,000 × 50% = £6,000 \text{ per instalment}]
1st Payment on Account (POA) – due 31 January 2025 = £6,000
2nd Payment on Account (POA) – due 31 July 2025 = £6,000
You will therefore have paid £12,000 on account by 31 July 2025.
Step 2 – File the 2024/25 tax return
Suppose your actual tax liability for 2024/25 turns out to be £13,500.
Step 3 – Work out the balancing payment
[Actual liability (£13,500)} − \text{Payments on account (£12,000)} = £1,500]
That £1,500 is your balancing payment, due 31 January 2026.
Step 4 – Calculate next year’s payments on account
HMRC will now base your 2025/26 expected liability on this latest figure (£13,500), unless you claim to reduce it.
[£13,500 × 50% = £6,750 \text{ per instalment}]
So your next two payments on account will each be £6,750, due 31 January 2026 and 31 July 2026.
Step 5 – If your income drops
If you know your 2025/26 profits will be lower, you can apply to reduce your payments on account. For example, if you expect your liability to fall to £10,000, you can claim to reduce each POA to:
[£10,000 × 50% = £5,000]
If you reduce too much and end up owing more, HMRC will charge interest on the shortfall.
The expected liability under Self-Assessment (SA) is calculated based on statutory guidance outlined in Section 59A and Section 59B of the Taxes Management Act 1970, as referenced in your document.
Here’s how it works:
Starting point – prior year’s liability HMRC calculates your expected liability for the current tax year using your previous year’s total income tax and Class 4 NIC liability, less any tax already deducted at source (for example, PAYE or CIS).
Payments on account
You are normally required to make two payments on account, each equal to 50% of the previous year’s net liability.
These are due:
31 January during the tax year, and
31 July after the tax year ends. These advance payments are meant to cover your “expected” liability for the ongoing year.
Adjustments and balancing payment
Once your Self Assessment tax return is filed, HMRC calculates the actual liability for the year.
The difference between the actual amount owed and what has already been paid on account becomes your balancing payment, due by 31 January following the end of the tax year (Section 59B (1) – (4)).
Reductions or claims
You may make a claim to reduce your payments on account under Section 59A(3) and (4) if you reasonably expect your current year’s income to be lower.
However, excessive reductions made negligently or fraudulently can attract penalties under Section 59A(6).
So in summary:
Expected SA liability = 100% of the prior year’s net income tax and Class 4 NIC liability (excluding tax deducted at source), paid as two equal instalments on 31 January and 31 July. Any remaining balance is paid the following 31 January once the actual figures are known.
Partnership appeals have specific procedures that differ significantly from individual appeals. Here’s how HMRC handles them:
Who Can Make Partnership Appeals
Strict Authority Requirements:
Must be made by the nominated partner on behalf of all relevant partners
OR by an authorized agent acting for the partnership/nominated partner
Appeals from non-nominated partners will be refused
Tribunals may reject appeals not made by the nominated partner
Verification Process: If it’s unclear who the nominated partner is, HMRC will:
Issue SEES form SA670 to confirm the nominated partner’s name
Make a Free Format Note on the Partnership record noting either:
“DD/MM/YY SA670 received. Nominated partner is [name]”
“YY/YY box 11.3 shows nominated partner as [name]”
Alternative Acceptance: Appeals can be accepted from:
Partner shown in box 11.3 on internet-filed returns (current or previous year)
Person who signed the paper return (if box 11.3 is empty)
Agent acting for all partners (though verification may be needed for large partnerships)
Special Circumstances
Death of Nominated Partner:
Successor is generally the person nominated by majority of other partners
Must include personal representative of deceased partner in the majority
SEES form SA670 must be issued to confirm new nominated partner
Agent Representation:
Can accept from agent acting for all partners
For large partnerships (hundreds of partners), practical verification may not be possible
Issue SA670 to confirm nominated partner details
System Recording Process
Unique Aspects for Partnerships:
Record Location:
Appeal recorded only on partnership record
Do NOT record on individual partner records
Use penalty imposition date as charge creation date (may need to check partner records to find this)
Standover Procedures:
Informal standover penalty in full on each individual partner’s record
Note work list items: “Working with Partnership, responsible office and UTR”
Not necessary to record appeal on individual partner records
Cross-Reference Management:
Partner records should note any work list items
Include reference to partnership responsible office
Maintain clear audit trail between partnership and individual records
Settlement Process
When Appeal is Settled:
Update Individual Records:
Where possible, update each individual partner’s record
Reduce standovers to nil
If direct updating not possible, inform responsible office for each partner
Tribunal Considerations:
Ensure tribunal understands they’re considering penalties on all partner records
Provide clear documentation of all affected partners
Communication:
Notify all relevant offices of settlement outcome
Ensure consistent treatment across all partner records
Penalty Application Rules
Late Filing Penalties:
All partners charged if partnership return not filed by due date
Appeals must go through nominated partner
Try to settle immediately if possible
Processing Approach:
Handle through partnership record using nominated partner authority
Apply informal standovers to individual partner penalties
Maintain coordination between partnership and individual records
Administrative Notes
Work List Management:
Appeals appear on partnership work list
Individual partner standovers noted separately
Cross-referencing essential for tracking
Documentation:
Retain clear records of nominated partner status
Document any changes in partnership composition
Maintain audit trail for tribunal purposes
Quality Control:
Regular review to ensure all partner records updated
Coordinate between multiple responsible offices if needed
Monitor for prompt settlement across all affected records
This partnership-specific process ensures that while the appeal is centrally managed through the nominated partner, the practical effects (like standovers) are properly applied to all affected individual partner records, maintaining both legal compliance and administrative efficiency.
A reasonable appeal typically involves either factual grounds or reasonable excuse. Here’s what counts:
Valid Grounds for Appeal
Factual Appeals
The assessment, penalty, or charge is factually incorrect
The return was actually filed on time
Payment was made on time
An agreed Time to Pay arrangement was already in place
Reasonable Excuse Appeals
A reasonable excuse is something that prevented the taxpayer from meeting their obligation despite taking reasonable care. It must be based on circumstances outside their control.
What HMRC Typically Accepts as Reasonable Excuse
Health-Related
Serious illness preventing the taxpayer from filing/paying
Mental health conditions (like PTSD) that impacted decision-making ability
Hospitalization that prevented dealing with tax affairs
Death of spouse/close relative that significantly impacted ability to meet obligations
External Circumstances
COVID-19 pandemic impacts (widely accepted during the relevant period)
Fire, flood, or theft that destroyed records or prevented filing
Postal service disruption (with certificate of posting showing timely dispatch)
HMRC online service failures with error messages as evidence
Technical Issues
Computer/software failure just before filing deadline
Delayed HMRC activation codes (if requested before deadline)
Loss of tax records through circumstances beyond control
What HMRC Does NOT Accept
Explicitly Excluded by Law
Shortage of funds (unless due to events completely outside taxpayer’s control)
Reliance on another person (unless specific conditions met)
Commonly Rejected Reasons
Pressure of work
Tax return being “too difficult”
Failure by tax agent
Lack of information from third parties
Not knowing how much tax to pay
Absence of HMRC reminders
Cheque made out incorrectly
Lack of free HMRC software
Key Requirements
Timing: Appeals must be made within 30 days of the notice (37 days allowed for processing)
Writing: Should be in writing, though some telephone appeals accepted
Authority: Must be made by the taxpayer, authorized agent, or (for partnerships) the nominated partner
Prompt Action: Once the reasonable excuse ends, taxpayer must act without unreasonable delay (typically within 14 days)
Special Considerations
Each case is assessed on its individual facts and circumstances
What’s reasonable for one person may not be for another based on their abilities
HMRC considers the taxpayer’s overall ability to manage their affairs during the period
Disability may be relevant if it specifically prevented compliance, but existing disabilities require contingency planning
The key test is whether the circumstances genuinely prevented the taxpayer from meeting their obligations despite taking reasonable care, and whether they acted promptly once the excuse ended.
Penalty and surcharge provisions (Sections 59C, 93, 93A)
Interest calculations (Section 86)
Taxation of Chargeable Gains Act 1992 (TCGA 1992) – Covers capital gains aspects including loss carry-back provisions
Supporting Legislation
Finance Acts 2008 & 2009 – Modern updates including:
HMRC set-off powers (FA 2008)
Updated interest calculation rules from 2011 onwards (FA 2009)
The Income Tax (Pay As You Earn) Regulations 2003 (SI 2003/2682) – Governs PAYE interactions with self-assessment
This legislative framework creates a comprehensive system covering filing obligations, payment schedules, penalties, interest calculations, and HMRC’s administrative powers for self-assessment.