A report issued by the National Audit Office (NAO) on 27 February 2026 (Taxing large businesses) examined HMRC’s approach to large business tax compliance. It found that the approach offers taxpayers good value for money, that large businesses rate their experience of dealing with HMRC highly, relative to other customer groups, and the size of the large-business tax gap, relative to revenue, is low. However, the report noted that large businesses also feel HMRC often asks for large volumes of data without making it clear how it plans to use the information.
Subsequently, the Public Accounts Committee (PAC) opened an inquiry (Large business tax compliance) in the course of which it has taken evidence from senior HMRC officials as it scrutinises the processes surrounding large business tax compliance. The evidence session is scheduled for 18 May 2026.
The PAC also invited wider views on the subject, which drew responses from a mix of ‘trade bodies’ and NGOs. Some of the points made in the responses are interesting, though it remains to be seen whether any will be taken up in the sessions with HMRC.
Chartered Institute of Taxation (CIOT) response
The CIOT notes that the customer compliance manager (CCM) model generally works well although there are some concerns about CCMs being unable to resolve issues. It adds that CCMs are most effective when they understand the sector and stay in place long enough to understand the company. It would support extension of the cooperative compliance model and CCMs, noting that businesses which are large but not large enough to have a CCM currently have additional burdens without additional support.
It raises concerns about HMRC requesting considerable, and often seemingly excessive, amounts of information, at times “overstepping their statutory powers and with little thought to the cost to business”. It suggests that HMRC needs to be clear on the purpose of each data request and what they intend to do with the information and communicate this clearly to businesses.
Finally, it suggests that if a business has a cooperative relationship with HMRC and has achieved a low-risk rating this should be taken into account when considering compliance interventions.
Association of British Insurers (ABI) response
The ABI notes that the majority of insurers are classed as large businesses by HMRC and have a CCM. It recommends that HMRC extends the CCM model to all groups containing regulated insurers to reflect the particular complexity of the industry. However, it notes a recent trend for CCMs to become more reliant on technical specialists and recommends facilitating taxpayer access to these specialists to make enquiry processes more efficient as well as providing clear timescales for resolution of disputes which the HMRC specialist teams are required to adhere to.
The ABI also notes that HMRC does not always appear to consider wider government policy when applying tax law. It also highlights occasions where HMRC’s interpretation of legislative requirements conflicts with industry’s and seeks a clearer resolution process.
It notes well-run, highly regulated insurers often spend significant time and resources maintaining as low a risk rating under HMRC categorisations as possible. However, it points out that the benefits of being low risk are diminished when a one-size-fits all approach is applied, such as when one-to-many letters are sent to all taxpayers in scope without reflecting the risk profile known to the CCM.
Finally, it argues that the process of agreeing VAT partial exemption special methods, which need to be updated as businesses change, is cumbersome. This often takes many years (six years being not uncommon) with HMRC’s approach often including a revisiting of issues previously thought to be settled.
UK Finance response
UK Finance notes that its members report a clear shift in HMRC’s operating approach, resulting in greater friction, reduced certainty and increased administrative burden. It suggests that its members are reporting a noticeable reduction in HMRC’s willingness to exercise pragmatic judgement, with interactions becoming increasingly process-driven. This is turn means that CCMs often lack discretion to resolve issues, with decisions escalated to internal specialists who have no knowledge of the taxpayer’s business or compliance record. There is also reduced willingness to apply materiality thresholds or close issues proportionately. Enquiries can be open for years with continuous, extensive and, at times, disproportionate information requests.
It also notes that clearance processes have become slower and significantly less predictable. It suggests it may be appropriate to update HMRC’s Departmental Strategic Objectives, as set out in its Annual Report to explicitly reference growth, competitiveness and efficient administration. It also calls for the low-risk profile of regulated financial institutions, especially Code of Practice banks, to be recognised and compliance approaches tailored accordingly.
Finally, it calls for “systemic failures” in HMRC digital systems, especially the VAT Business Tax Account, to be addressed with urgency.
Fair Tax Foundation response
The Foundation calls for the PAC to champion the need for the UK to take an international lead on public country-by-country reporting by the world’s largest multinationals. It suggests that the focus would be those multinationals that are already required to capture country-by-country data and share it with tax authorities privately (i.e., those with an annual consolidated turnover of at least €750m).
It calls for the UK Government to align but improve upon the baseline EU pCbCR disclosure requirements so that the UK could consider:
- Augmenting the EU’s list of ‘tax havens’ with the UK’s list of Overseas Territories and Crown Dependencies
- Requiring public country-by-country reporting (pCbCR) filings to be published both at Companies House and on the parent company’s website
- Not offering a “safeguard clause”, whereby businesses defer disclosure for up to five years on the basis of ‘commercial sensitivity’
- Implementing substantial fines for non-compliance, of up to c.£500,000
Tax Justice response
The Tax Justice submission also calls for corporate reporting of profits to be made more transparent with the introduction of pCbCR and support for the principles of the United Nations Tax Convention. In a similar vein to the Fair Tax Foundation, it argues that the PAC should look at the role of the British Overseas Territories and Crown Dependencies in fuelling the offshore tax gap for large companies.
Finally, it calls on the PAC to look at the wider tax architecture as part of its investigation or a future inquiry, in particular the excessive length of the tax code and assessment of reliefs.
Tax Watch response
The Tax Watch submission is heavily focused on the role that MAP plays in international tax issues. It calls for HMRC to set out revenue guardrails in the Litigation and Settlement Strategy for HMRC’s approach to Mutual Agreement Procedures (MAP), as it does for domestic tax settlements. It also asks for HMRC to disclose how many Mutual Agreement Procedures in the last five years have been decided by arbitration, what was the amount of tax at stake, and in how many was HMRC’s position selected by the arbitrators.
It makes the point that HMRC has previously insisted that the Diverted Profits Tax (DPT) is out of scope of these treaty-mandated processes. However, it argues that legislative changes in Finance Act 2026 are intended to ensure that in future taxpayers can insist on such processes in DPT cases too.
The submission also includes a ‘case study’ focusing on what it describes as a “a £1.5 billion large business tax dispute”, which is covered in more detail in a separate Tax Watch report.