Tax Investigations, Prosecutions & Appeals

Q: Early risk triage & strategy

Assess exposure, evidence and likely HMRC approach Coordinate experts (forensic accounting, valuations) Manage communications with HMRC and affected stakeholders.

Q: COP8 (complex avoidance & technical disputes)

Respond to COP8 enquiries focused on tax avoidance, complex technical matters and large risks Develop technical and factual positions, including alternative analyses and settlement options Negotiate interest and penalty positions, and secure pragmatic outcomes.

Q: Tax tribunals (litigation)

Robust representation before the First-tier Tribunal (Tax) and Upper Tribunal. Case strategy, pleadings, witness/expert evidence and advocacy Appeals, closure notice disputes, discovery assessments, information notice challenges and judicial review interfaces Settlement opportunities preserved alongside litigation to optimise outcomes.

Q: Criminal tax investigations & prosecutions

HMRC can pursue criminal investigations where they suspect fraud, evasion or deliberate wrongdoing Representation upon arrest, interviews under caution and search warrants We guide clients through every stage, from voluntary interviews to full trial representation

HMRC has significant civil and criminal powers to investigate tax irregularities, unpaid tax, offshore issues, tax fraud and tax evasion.

Being investigated by tax and financial authorities can be distressing, disruptive to your personal and professional life, time-consuming and high-stakes. Our experienced team can help defend you from any allegations of financial irregularity and reduce the impact on your life as much as possible.

Strategic defence and resolution for individuals, businesses and advisers

HMRC are becoming more sophisticated in the use of data to assist their risk-profiling of taxpayers. That means there is a greater chance that HMRC will identify those taxpayers who have not paid the correct amount of tax. The level of penalties for making a mistake with your tax affairs can be severe. That makes an early assessment of your position essential.

Our specialist team has experience helping a wide range of individuals and businesses. We will act quickly to protect your position, manage risk and deliver the best available outcome.

We can assist with:

HMRC enquiries
Other HMRC disputes and investigations
Tax fraud
Alternative Dispute Resolution
Complex & International enquiries
First tier Tax Tribunal / Upper Tribunal
Criminal investigations and prosecutions
Code of Practice 8 (COP8) investigations (tax avoidance)
Code of Practice 9 (COP9) investigations (where HMRC suspects tax fraud)
Missing Trader Intra-Community (MTIC) fraud investigations (carousel fraud)
Liechtenstein Disclosure Facility, crown dependency disclosure facilities and other disclosure facilities.

Practical guidance

Do not ignore deadlines – especially the 60-day COP9 response window
Keep communications controlled – route everything through your legal team to preserve privilege
Evidence wins – bank statements, contractual documents, board minutes, valuations and contemporaneous records are critical
Consider Alternative Dispute Resolution (ADR) early – it can unlock impasses cost-effectively.

Why Irwin Mitchell?

Specialist team with deep experience in COP8, COP9, high net worth and corporate enquiries.
End-to-end support: from initial disclosure and HMRC engagement to negotiating settlement agreements, Tribunal litigation, and criminal investigations and prosecutions.
Integrated expertise across tax, regulatory/criminal, corporate, private client, employment and reputation management.
Calm, commercially focused advice that balances legal, financial and reputational considerations.
Discreet and responsive – we move quickly to protect your position from day one.

What we do

Early risk triage & strategy

COP8 (complex avoidance & technical disputes)

COP9 & the Contractual Disclosure Facility (CDF)

Advise on whether to accept COP9 and enter the CDF - the civil route for suspected deliberate behaviour
Prepare the Outline Disclosure within the 60-day window and manage the full report thereafter
Mitigate penalties via complete disclosure, cooperation and quality of evidence, protect individuals from criminal referral where possible
Handle parallel employer, director, and adviser considerations
Complex, Offshore & High Net Worth.

Tax tribunals (litigation)

Criminal tax investigations & prosecutions

Frequently Asked Questions

What happens in an HMRC tax investigation?

HMRC carries out three main types of tax investigation: a Section 9A enquiry, a Code of Practice 8 (COP8) and Code of Practice 9 (COP9).

These investigations are not criminal investigations and don’t always lead to criminal prosecution. However, HMRC can start criminal investigations and prosecution if you don’t comply or if they find evidence of serious offences.

Section 9A enquiries are used by HMRC to review information entered on your self-assessment tax return. These can relate to a particular aspect of your tax return or a random review of your submission. They are usually conducted through written communication with HMRC.

COP8 investigations are used if HMRC suspects you of tax avoidance or minor fraud. They usually involve a series of informal meetings and correspondence between you and HMRC to identify any underpaid tax.

COP9 investigations are used when HMRC suspects you of serious fraud but hasn’t started a criminal investigation. You must give HMRC a detailed report about your tax affairs, as well as anything you have done that has caused any irregularities, whether deliberate or not.

Once the investigation has settled on a value for any unpaid tax (including interest), you and HMRC negotiate a penalty payment based on your behaviour before and during the investigation. You will pay less of a penalty if you are helpful and cooperative.

Will I have to go to court if I’m being investigated by HMRC?

Most civil tax investigations end with you and HMRC agreeing on how much tax and how much of a penalty you should pay. You don’t need to go to court if this is the case.

If you can’t reach a mutual agreement and disagree with HMRC’s decision on the case, you can make an appeal and begin litigation either in civil court or a tribunal.

If HMRC starts a criminal investigation against you and finds evidence of criminal offences, you may have to go to court to face criminal prosecution.

Whatever type of tax dispute you are involved with, it is vital to seek legal advice and representation as early as possible. This will give you the best chance of resolving your dispute without going to court.

If you do have to go to court, our solicitors can also advise, represent, and support you throughout.

What if I disagree with an HMRC decision?

If you are unhappy with the outcome of the HMRC investigation, you can request an internal review. This will be carried out by another HMRC officer who has no previous involvement with the case. They can either confirm or change the figures of the original investigation.

If you are still unhappy, you can appeal the decision in a civil court or tribunal, which starts the litigation process.

During litigation, you and HMRC will present evidence for your different tax calculations. The court or tribunal will decide on the correct tax figure.

If they find that you have underpaid, you will get a deadline to pay the difference, plus interest and a penalty payment. You may be allowed to make payments in instalments.

If you fail to make any required payments, you may face criminal prosecution.

Which tax offences might attract criminal prosecution?

Although HMRC handles minor tax avoidance and fraud cases with civil litigation, more serious offences risk criminal prosecution. These can include:

VAT evasion
Money laundering
Income tax evasion
Cheating the public revenue
Providing false documents or information to HMRC
Smuggling or fraudulent evasion of excise duty on imported goods (e.g. cigarettes, alcohol).

There are now more criminal prosecutions for tax offences than ever before. If you are facing tax litigation of any kind, you must get legal advice as soon as possible. Contact us today for a confidential chat with our experts.

What penalties could I face for tax offences?

You must pay any unpaid tax along with interest calculated since the date the tax was due. The additional penalties will depend on what type of litigation you are going through:

Civil: You can negotiate a monetary penalty with HMRC based on the amount of unpaid tax, whether or not the missed payment was deliberate, and how cooperative you have been during the investigation. If you can’t negotiate a penalty, it will be decided in court or tribunal. HMRC can publicly publish information about penalties above certain thresholds.
Criminal: A criminal prosecution can result in a fine, imprisonment or both. In either case, you must still pay back the tax as well. You may also be ordered to pay the prosecution’s costs. Tax evasion is taken extremely seriously and is often punished with severe penalties.

You may also be prosecuted under the Proceeds of Crime Act 2002 and the Money Laundering Regulations 2017. Your possessions can be confiscated if you are convicted of money laundering.

Our solicitors may be help you avoid civil or criminal penalties or negotiate less severe penalties. Contact us for more information.