HMRC Crypto Information Requests: What UK Taxpayers Must Disclose

Cryptocurrency has moved rapidly from the margins of finance into mainstream investment and commercial use. Millions of UK taxpayers now hold, trade, or transact using cryptoassets, including Bitcoin, Ethereum, stablecoins, and a wide range of tokens used for investment, trading, decentralised finance (DeFi), and online payments. Alongside this growth, HM Revenue & Customs (HMRC) has significantly intensified its compliance activity in relation to crypto taxation.

Recent announcements confirm that cryptocurrency users must now share detailed information with HMRC as part of a wider crackdown on perceived tax evasion and non-compliance. Through expanded data-gathering powers, international information exchange, and cooperation with crypto exchanges, HMRC is increasingly able to identify individuals and businesses who have failed to declare crypto gains, income, or transactions correctly.

Why HMRC Is Cracking Down on Cryptocurrency

HMRC has made no secret of its view that crypto assets present a significant compliance risk. The decentralised nature of cryptocurrency, historic assumptions about anonymity, and the rapid pace of innovation have led HMRC to conclude that under-reporting is widespread.

In recent years, HMRC has invested heavily in specialist crypto compliance teams, blockchain analytics software, international data-sharing arrangements and targeted “nudge letters” and formal enquiries.

Public reporting indicates that HMRC believes billions of pounds in tax may have gone undeclared through crypto transactions. This perception has driven a more aggressive enforcement posture, particularly towards individuals who have traded frequently, used offshore exchanges, or participated in DeFi and staking arrangements without understanding the tax consequences.

Crucially, HMRC’s strategy is no longer reactive. It is now proactively gathering data and matching it against Self Assessment returns, PAYE records, and known wallet activity.

The Legal Basis for HMRC Demanding Crypto Information

HMRC’s powers to obtain information about cryptocurrency users derive from multiple sources of UK tax law and international cooperation frameworks.

Domestic Information Powers

Under Schedule 36 to the Finance Act 2008, HMRC can issue information notices to taxpayers and third parties requiring the production of documents and data reasonably required to check a tax position. These powers apply equally to crypto exchanges, wallet providers, and other intermediaries operating in or with the UK.

Failure to comply can result in penalties, and in serious cases, enforcement action through the courts.

International Data Exchange

HMRC is also implementing international crypto reporting frameworks designed to remove cross-border opacity. These regimes require cryptoasset service providers to collect and share detailed user information, including:

• identity details;
• transaction histories;
• wallet addresses; and
• value of holdings and disposals.

This information is then shared between tax authorities, meaning offshore exchanges are no longer a reliable shield against UK tax scrutiny.

For taxpayers who assumed that historic crypto activity would remain invisible, this represents a fundamental shift in enforcement capability.

What Crypto Users Must Disclose to HMRC

HMRC expects UK taxpayers to declare all taxable crypto activity accurately and in full. This includes, but is not limited to:

• disposals of crypto assets subject to Capital Gains Tax;
• income from mining, staking, or DeFi lending;
• airdrops received in return for services or activities;
• crypto paid as employment income or trading receipts; and
• profits arising from frequent or organised trading activity.

Importantly, HMRC does not accept that cryptocurrency is “outside” the tax system. Its Crypto assets Manual makes clear that tax treatment follows established principles of income tax, corporation tax, and capital gains tax, applied to the specific facts of each case.

Disputes often arise not because taxpayers deliberately sought to evade tax, but because the technical analysis is complex and HMRC’s interpretation is not always straightforward or consistent.

How a Crypto Enquiry Typically Arises

By way of illustration, consider a UK-resident individual who began trading cryptocurrency several years ago using a combination of UK and overseas exchanges. Over time, they made multiple trades, transferred assets between wallets, and participated in staking and token swaps. Gains were reinvested rather than withdrawn to fiat currency.

Several years later, HMRC issues a letter stating that it has received information suggesting the individual has engaged in crypto transactions and asking them to review and amend their tax returns. The letter may initially appear informal, but it often marks the beginning of a formal compliance check.

When HMRC later opens an enquiry, it requests full transaction histories, wallet addresses, exchange statements, and explanations of the taxpayer’s activities. It may also indicate that penalties are being considered under Schedule 24 Finance Act 2007.

HMRC’s Common Arguments in Crypto Tax Disputes

In crypto enquiries, HMRC frequently advances a number of recurring arguments.

Under-Declaration of Capital Gains

HMRC often asserts that taxpayers failed to calculate gains correctly, particularly where multiple transactions, token swaps, or transfers between wallets occurred. The application of pooling rules and valuation in sterling frequently becomes contentious.

Misclassification of Income vs Capital

Another common dispute concerns whether crypto activity amounts to investment (subject to CGT) or trading (subject to income tax). HMRC may argue that frequency, organisation, and intention indicate a trading activity, significantly increasing tax exposure.

Failure to Declare Staking or DeFi Income

Many taxpayers are unaware that staking rewards, yield farming returns, or certain airdrops may constitute taxable income at the point of receipt. HMRC increasingly scrutinises these activities.

Allegations of Careless or Deliberate Behaviour

Where HMRC believes that a taxpayer “should have known” about their obligations, it may assert careless or deliberate conduct, triggering substantial penalties. These behavioural characterisations are often contestable.

The Role of Penalties and the Importance of Behavioural Analysis

Penalty exposure frequently represents the most significant financial risk in crypto disputes. Under Schedule 24 FA 2007, penalties depend on whether inaccuracies were careless, deliberate, or deliberate and concealed.

HMRC often adopts an aggressive stance, particularly where crypto activity was not disclosed at all. However, Tribunals have repeatedly emphasised that complexity, novelty, and reliance on professional advice are highly relevant to the question of reasonable care.

In many cases, it is possible to demonstrate that the taxpayer acted in good faith, misunderstood complex rules, or relied on incomplete guidance. Successfully reframing behaviour can dramatically reduce or eliminate penalties, even where tax is ultimately payable.

How Crypto Disputes Are Resolved

Resolution pathways vary depending on the facts, but typically include, structured written representations to HMRC, voluntary disclosure or amendments where appropriate, internal HMRC reviews, and appeals to the First-tier Tribunal (Tax Chamber).

Tribunal decisions in tax cases consistently show that HMRC’s guidance is not determinative. The Tribunal applies statute, case law, and evidence, often rejecting HMRC’s assumptions where they are not supported by law.

Early legal intervention is critical. Poorly framed responses or incomplete disclosures can harden HMRC’s position and increase penalty risk unnecessarily.

Interaction with Wider Enforcement Powers

Crypto tax enquiries rarely exist in isolation. HMRC may also consider:

• assessments against companies where crypto was used in business;
• enquiries into directors or partners;
• unexplained wealth or lifestyle discrepancies; and
• insolvency or enforcement action where liabilities are significant.

In high-value cases, HMRC may escalate matters to its Fraud Investigation Service, dramatically increasing complexity and risk.

Why Specialist Advice Matters in Crypto Tax Investigations

Cryptocurrency disputes sit at the intersection of tax law, technology, and evidence. They require more than basic accounting input. Understanding blockchain records, exchange data, and the legal characterisation of novel transactions is essential.

LEXLAW’s specialist tax disputes team regularly advises individuals and businesses facing HMRC crypto enquiries. The team combines technical tax expertise with litigation experience, allowing disputes to be handled strategically rather than reactively.

HMRC Cryptocurrency Tax Disputes: Legal Advice & Representation

HMRC’s crackdown on cryptocurrency is intensifying, and the risks of inaction are increasing. What may begin as a simple request for information can quickly escalate into a multi-year dispute involving significant tax, penalties, and enforcement action.

LEXLAW provides specialist legal advice and representation in cryptocurrency tax disputes, compliance checks, and appeals. Our focus is on controlling the narrative, applying the correct legal framework, and securing proportionate outcomes that protect our clients’ financial and commercial position.

If you have received correspondence from HMRC concerning cryptocurrency, or are concerned about historic non-disclosure, early specialist advice is essential. Timely intervention can prevent escalation, mitigate penalties, and significantly reduce overall exposure. Contact us today for expert legal guidance and proactive representation.