Challenging HMRC and Police Search Warrants: Judicial Review and Legal Representation
An HMRC or police search warrant can be challenged through judicial review where it was issued unlawfully. The execution of the search, protection of privileged communications and continued retention of seized material may also require separate legal action.
Andrew Mountbatten-Windsor’s successful judicial review of search warrants obtained by Thames Valley Police has brought renewed attention to when searches can be challenged.
For individuals and businesses facing a search, the immediate questions are practical: was the warrant lawful, can investigators examine confidential legal advice, and can seized documents, phones or computers be recovered?
Successful challenges show why these questions deserve careful examination. Courts have set aside warrants because investigators materially misled the issuing judge, failed to establish the required grounds for suspicion or used the wrong statutory procedure.
Michael Paulin is a barrister practising in tax disputes and public law, accepting suitable direct access instructions. He works closely with leading solicitors’ firms and can make recommendations where appropriate. An initial assessment can identify potential grounds of challenge, any need for urgent protection and the remedies worth pursuing. Contact Michael.paulin@1cor.com
Can you challenge a search warrant approved by a judge?
Yes. Judicial approval does not make a search warrant immune from challenge.
Judicial review examines whether the decision to issue it was lawful. The court’s permission is required, and the appropriate procedure depends on the statutory power and circumstances. A challenge must identify a legal defect: disagreement with the investigation is insufficient.
The starting point is to obtain and examine the warrant, its supporting application and, where available, the record of the hearing. The question is whether the legal requirements were satisfied on a properly presented evidential basis.
How quickly should you seek legal representation?
Seek advice promptly after learning of the warrant or search.
Under CPR 54.5, a judicial review claim generally must be filed promptly and, in any event, within three months after the grounds first arose. The three-month limit is not permission to wait. An urgent application for interim protection may require consideration where examination of seized material is imminent.
Preserve the warrant, notices, seizure inventory, correspondence and a factual account of the search. Identify any privileged communications among the seized material and explain any immediate business disruption.
What can make an HMRC or police search warrant unlawful?
Different statutory powers impose different conditions. A specialist assessment should examine:
The statutory basis: was the correct power used?
The evidence: were the required grounds for belief or suspicion established?
Disclosure: did investigators present relevant information fairly, including matters weighing against the application?
The scope: were the premises and material sufficiently identified?
Protected material: was legal privilege or special procedure material properly addressed?
Section 15 of the Police and Criminal Evidence Act 1984 (“PACE”) contains safeguards governing warrant applications, including identifying, so far as practicable, the articles or persons sought.
Applications are ordinarily made without the affected person present. The applicant’s duty of candour is therefore an essential safeguard: material information unfavourable to the application must be placed before the court.
The following cases demonstrate how those safeguards operate.
HMRC search warrants: Mercury Tax Group and material non-disclosure
In R (Mercury Tax Group Ltd and another) v HMRC and others [2008] EWHC 2721 (Admin), HMRC obtained warrants to search offices and clients’ homes during an investigation into the allegedly dishonest implementation of a gilt-strip tax avoidance scheme.
The applications were made under the then-applicable section 20C of the Taxes Management Act 1970. Underhill J found that HMRC had materially misled the issuing judge about whether clients knew of a change in the securities used. Letters showing that clients had been informed were not properly brought to the judge’s attention.
The court did not conclude that the original material could never justify reasonable suspicion. The successful challenge concerned the misleading presentation and material non-disclosure. The decisions to issue the warrants were held unlawful and fell to be quashed: see [48]–[58] and [65]–[72].
The practical lesson: compare the investigator’s account with the underlying documents. In a tax investigation, it is particularly important to examine the evidential basis for alleging dishonesty, rather than treating defects in a tax arrangement as sufficient proof of fraud.
SFO search warrants: Tchenguiz and misleading financial evidence
In R (Rawlinson & Hunter Trustees SA and others) v Central Criminal Court and another [2012] EWHC 2254 (Admin), the court considered SFO warrants concerning Robert and Vincent Tchenguiz and their business interests during an investigation into transactions involving Kaupthing Bank.
The court identified serious errors, material non-disclosure and failures to explain the transactions accurately. For Robert Tchenguiz and R20, a corrected and balanced presentation would have made a real difference: the judge would not have granted the warrants. The SFO had already conceded that warrants concerning Vincent Tchenguiz and Consensus could not stand.
The warrants were quashed. The court rejected an attempt effectively to reconstruct the original application during judicial review: see [170]–[179].
The practical lesson: complex commercial transactions require careful analysis. Representation may expose a significant gap between the financial evidence and the account of suspected criminality presented to the issuing judge.
Offshore businesses: Golfrate and insufficient grounds for suspicion
In R (Golfrate Property Management Ltd and another) v Crown Court at Southwark and another [2014] EWHC 840 (Admin), police obtained warrants under the Proceeds of Crime Act 2002 during an investigation into suspected money laundering connected with Zimbabwean sanctions.
After correcting misrepresentations and accounting for omitted information, the court concluded that the material did not withstand scrutiny as a basis for reasonable suspicion of the alleged money laundering. Offshore structures, political connections and suggestions of other questionable activities did not establish the necessary connection to that offence. The warrants were set aside: see [89]–[118].
The practical lesson: international transactions and offshore ownership require an evidenced explanation of how the particular suspected offence arises. The existence of a complicated structure does not answer that question.
Legal privilege and defective warrants: GSX
In R (GSX) v Crown Court at Southwark [2026] EWHC 538 (Admin), police acting for the FCA obtained a section 8 PACE warrant against a practising barrister. The application acknowledged that his devices were highly likely to contain privileged material.
The court identified defects concerning the access conditions, privileged and special procedure material, and the failure sufficiently to identify the articles sought. Unlawfulness was conceded; the warrant was quashed and the entry, search and seizures declared unlawful.
However, the court refused orders requiring immediate return, destruction of copies and a permanent prohibition on use. Retention was to be determined through section 59 of the Criminal Justice and Police Act 2001: see [16]–[30] and [97]–[106].
The practical lesson: representation must address both the validity of the warrant and what happens to the material afterwards. A successful challenge does not necessarily resolve every issue concerning retention or use.
Mountbatten-Windsor: using the wrong statutory procedure
The published order and reasons of Hilliard J dated 8 October 2026 in R (Andrew Mountbatten-Windsor) v Central Criminal Court and Chief Constable of Thames Valley Police, Claim No. AC-2026-LON-002321, provide a recent example.
The police conceded that section 8(1)(d) PACE could not properly have been satisfied. The application expressly envisaged privileged material, and the nature of the investigation implicated special procedure material.
The reasons identify section 9 and Schedule 1 as the alternative statutory route requiring consideration, subject to their conditions. That route does not remove legal privilege. The judicial review succeeded by agreement; the other four grounds were not determined: see [2]–[5].
The practical lesson: the nature of the material sought can determine which statutory procedure investigators must follow. Arrangements for reviewing seized material do not, by themselves, establish that the original warrant was lawfully issued.
Can investigators examine communications with your solicitor or barrister?
Legal professional privilege can protect confidential communications involving legal advice or litigation. Whether it applies depends on the purpose and circumstances of the communication.
Section 10 PACE defines items subject to legal privilege. Items held with the intention of furthering a criminal purpose are excluded from that protection.
Where a seized device contains legal communications, the immediate priority may be to identify the affected material and seek appropriate arrangements preventing examination pending resolution of privilege claims.
The assessment should distinguish legally privileged communications from other confidential records. Special procedure material may include records acquired or created in a business, profession or office and held subject to an undertaking of confidence; the statutory definition must be applied to the particular records.
What if officers exceeded their powers during the search?
The lawfulness of issuing a warrant and the lawfulness of executing it are separate questions.
PACE Code B governs searches and seizure, including their extent, safeguards for privileged material and records of property seized. Officers may also rely on powers beyond the warrant itself, so the legal basis for each disputed act needs examination.
A review should compare the warrant with what happened: which premises were entered, what was searched, what was taken and what explanation was given.
For a business, advice should also address the operational consequences of losing computers or essential records, including whether access or copies can be obtained.
Does quashing a warrant mean the investigation ends?
No. Nor does it automatically require immediate return of everything seized.
The Mountbatten-Windsor reasons explain that the investigation continued and record an outstanding application under section 59 to retain material: see [6].
A strategy should therefore address the original illegality alongside any asserted basis for continued retention. The objectives may include setting aside the warrant, protecting privileged material, recovering particular property or obtaining access to essential records.
HMRC uses PACE criminal investigation powers in England and Wales, including powers to apply for and execute warrants in suspected tax evasion cases. Some provisions are modified for HMRC. A criminal warrant challenge should be coordinated with the wider response to the investigation.
Instructing Michael Paulin to challenge a search warrant
Michael Paulin accepts suitable direct access instructions concerning tax disputes and public law. He also works closely with and is instructed by leading solicitors’ firms in this area. He is authorised to conduct litigation, with the scope of advice and representation agreed for each case.
Advice may include assessing grounds of challenge, protecting privileged material, preparing judicial review proceedings, considering urgent relief and responding to continued retention of seized property.
If your home or business has been searched by HMRC or the police, contact Michael Paulin Michael.paulin@1cor.com for an initial assessment. Provide the warrant and seizure inventory if available, the date of the search and details of any urgent concern about legal communications or essential business records.
This article concerns England and Wales and provides general information. The appropriate challenge and remedy depend on the warrant, statutory power and facts in issue.