Compliance
Modernised Company Tax Returns in the UK: What Businesses Need to Know
HMRC’s new consultation proposes standardised, fully tagged company tax computations—UK Corporations must prepare now for technical change and system adjustments.
By NomadicTax Research Team • 5-8 min read • March 29, 2026
## Overview of the UK Consultation
A consultation published in **March 2026** by HM Revenue & Customs titled *“Modernising and Standardising Company Tax Returns”* seeks input on creating **fully tagged, standardised tax computations** for company tax returns. ([gov.uk](https://www.gov.uk/government/consultations/modernising-and-standardising-company-tax-returns/modernising-and-standardising-company-tax-returns?utm_source=openai))
The proposal includes a multi-stage rollout:
- **Draft specifications** from April–September 2026.
- **Final prescribed format** published by end-September 2026.
- **Build and test period** from October 2026 to September 2027.
- **Live pilot** from October 2027 to September 2028. ([gov.uk](https://www.gov.uk/government/consultations/modernising-and-standardising-company-tax-returns/modernising-and-standardising-company-tax-returns?utm_source=openai))
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## Why It’s Critical for Compliance
- Tagging ensures computations are machine-readable and interoperable—offering accuracy but requiring software updates.
- Standardization reduces ambiguity in reports, helping avoid inconsistencies that lead to audits or penalties.
- Wider scope will influence financial systems; businesses must adapt data capture and processing to meet the new governance.
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## Who Will Be Affected
- Medium to large UK companies already using tax software.
- Accounting software vendors—they’ll need to build tools compliant with the new specification.
- Tax teams reviewing internal processes, documentation, and readying for audits.
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## Steps to Prepare
1. **Inventory your current filing software**: find out how updates are managed and when future changes are expected.
2. **Build internal capability**: document how your company computes tax, tracks adjustments, and maps accounts. Standardizing this internally makes external compliance easier.
3. **Engage with your software provider**: request roadmaps or early access to draft specifications.
4. **Pilot internally**: trial runs of tagged computations using your current data to identify gaps—missing fields or data sources.
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## Example
An e-commerce corporation files its Corporation Tax return annually using commercial tax software. Under the new proposal, each item of income, expense, adjustment, etc., would need a machine-tagged field. Items like “R&D expenditure” or “capital allowances” must map to prescribed tags. If data isn't captured in your ERP or record-keeping in tagged form now, retroactive correction will cost time and risk errors.
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## Key Takeaway
**Compliance Category**: Businesses covered need to start mapping their accounting and filing systems to the new prescribed format now, before draft specifications are finalized. Staying ahead reduces disruption when implementation begins in late 2026.