The Crime & Policing Act 2026 has received Royal Assent, and its reach goes well beyond financial crime. The HMRC mandatory register opens in ten days. The OBR has published its detailed forecast for the High Value Council Tax Surcharge. And ICAEW is removing obsolete content from its website to stop AI tools from serving practitioners misleading guidance.
Here is the detail.
Crime & Policing Act 2026 Expands Corporate Criminal Liability Beyond Financial Offences
The Crime & Policing Act 2026 has received Royal Assent, and it changes the basis on which UK companies can face criminal prosecution.
The 2023 Economic Crime Act introduced corporate liability for a defined list of financial offences: fraud, theft, and related conduct. The 2026 Act removes that boundary. A company can now be held criminally responsible for almost any offence committed by a senior manager acting within the scope of their corporate authority. The change is not limited to financial services or large organisations. It applies across sectors and business sizes.
Who counts as a senior manager now carries legal weight that they did not before. Governance structures that have not been reviewed recently, and whistleblowing protocols that route concerns externally before capturing them internally, are both potential liabilities.
Experts are recommending three immediate actions for affected firms: conduct an urgency audit of governance procedures, re-identify who qualifies as a senior manager under the new test, and review whistleblowing arrangements to ensure internal risks are documented before they escalate.
Key facts:
- The 2023 Economic Crime Act covered theft, fraud, and related financial offences only
- The 2026 Act extends liability to the full spectrum of criminal risk
- A company is liable where a senior manager commits an offence within the scope of their authority
- Governance audits, senior manager mapping, and whistleblowing protocol reviews are the recommended response
For clients with complex management structures or recent leadership changes, this is the week to start that conversation.
10 Days to the HMRC Register: Key Deadlines from May to August
The HMRC mandatory register for tax agents and conveyancers opens on 18 May. Anyone paid to interact with HMRC on a client’s behalf must register or lose the ability to act.
Registration is not optional, and the scope is broader than many firms initially assumed. The 18 May date marks the launch of the register, but requirements are staggered. The first wave of new registrants must complete the process by 18 August. Those with existing Self Assessment or Corporation Tax accounts only begin their registration window on that date, with a final deadline of 18 November. Third-party payroll businesses follow with their window opening on 18 November.
Behind the register, a sequence of further deadlines runs through to August that will put pressure on practice management over the next three months.
Key Facts:
- 18 May 2026 – HMRC mandatory register opens for new tax agents and conveyancers
- 31 May 2026 – Deadline for employers to issue P60s
- 6 July 2026 – P11D and P11D(b) submission deadline; Employee Related Securities and EMI options reporting due
- 31 July 2026 – Second payment on account for self-assessment
- 7 August 2026 – First quarterly update deadline for MTD for Income Tax, affecting those with self-employed or property income above £50,000
- 18 August 2026 – Registration window opens for existing Self Assessment or Corporation Tax account holders; deadline for the first wave of new registrants
- 18 November 2026 – Final registration deadline for existing Self Assessment or Corporation Tax account holders; registration window opens for third-party payroll businesses
The August window compresses MTD, payment on account, and the registration deadline into a short stretch. Map these dates against your client list now.
OBR Sets Out the Numbers Behind the High Value Council Tax Surcharge
The OBR has published its detailed forecast for the High Value Council Tax Surcharge, introduced in the 2025 Budget and set to take effect in two years. Approximately 165,000 households fall within the scope.
Properties valued between £2 million and £2.5 million will face an annual charge of £2,500. Those above £5 million will face £7,500. The OBR expects 20% of affected owners to appeal their valuations, with a projected 40% success rate. Successful appeals are expected to erode total tax yield by around 4%.
The secondary consequences are equally significant. The OBR forecasts that wealthy owners will downsize to fall below the threshold, resulting in a £215 million reduction in Stamp Duty receipts and a £65 million reduction in Inheritance Tax yield. The rollout itself carries a £400 million implementation cost, including £120 million for property valuations.
Key facts:
- 165,000 households expected to be affected
- £2,500 annual charge for properties valued between £2m and £2.5m; £7,500 above £5m
- 20% of owners expected to appeal valuations; 40% projected success rate
- £400m rollout cost, including £120m for property valuations
- Projected secondary losses: £215m in Stamp Duty, £65m in Inheritance Tax
Clients in the affected valuation bands need advice on the appeal process and on whether restructuring decisions made in anticipation of the surcharge carry unintended IHT or CGT consequences.
ICAEW Removes Outdated Content to Stop AI Tools Misleading Practitioners
ICAEW is auditing and restructuring icaew.com, removing obsolete guidance from its technical and professional resources.
Generative AI tools pull from publicly available web content. Outdated material on authoritative sites creates a specific risk: a practitioner or client using an AI tool may receive an answer based on superseded rules, presented with apparent authority. The UK government is running a parallel exercise on gov.uk for the same reason.
The restructure introduces a combined “Technical guidance and news” hub and a new “Policy and research” section covering the Institute’s economic analysis, VAT reform proposals, and Business Confidence Monitor. The former “Insights” label was replaced with “News” in April 2026.
For practitioners who use AI tools internally or recommend them to clients, the ICAEW exercise is a useful prompt. Outdated professional guidance sitting online is a liability that most firms have not yet considered.
Also In News & Updates
- Law Firm Accounting Breaches and SRA Closures | FigsFlow – Accounting failures account for a disproportionate share of SRA-mandated firm closures, new data shows.
- HMRC’s New Sanctionable Conduct Powers Explained – What the new conduct framework means for registered and unregistered advisers.
- Companies House WebFiling Flaw Exposed 5 Million Companies – A security vulnerability in the WebFiling system exposed the majority of registered UK companies to fraudulent filings.
- Tax Adviser Registration for Financial Firms Delayed to 2027 – Financial services organisations receive a later deadline as HMRC refines the registration framework.
- Weekly News & Updates for UK Accountants (1 May 2026) | FigsFlow – Last week’s round-up covering the stories that shaped the week for UK practitioners.
Conclusion
The expansion of corporate criminal liability is the most structurally significant change this week. Governance structures and whistleblowing protocols that have not been reviewed recently are now a legal exposure.
The HMRC registration deadline is the most immediately urgent. Ten days is not much runway, and the deadlines stacking up behind it leave little room for reactive practice management.
The OBR’s HVCTS figures give advisers the numbers they need for client conversations. The ICAEW content audit raises a question worth asking about every AI tool currently in use: what is it drawing on, and how current is it?
Follow along for next week’s updates as the deadlines continue to run.
