What triggers a COP8 investigation?

A COP8 case usually starts when HMRC believes your tax position doesn’t add up — typically because of:

• Use of tax avoidance schemes (especially marketed or offshore ones).
• Unexplained wealth, property ownership, or foreign income.
• Complex company or trust structures designed to reduce UK tax.
• Third-party information, such as banks or whistleblowers.
• Large discrepancies between reported income and lifestyle.

Sometimes it’s not about wrongdoing — it’s about patterns that don’t make sense to HMRC. They’re looking for undeclared income, or arrangements that look “too clever”

What are the consequences if I’m subject to COP8?

The consequences depend entirely on how you handle it.

A COP8 investigation can lead to:

• Tax repayment (for underpaid or wrongly avoided tax).
• Interest on that tax.
• Penalties (depending on whether HMRC thinks it was careless or deliberate).
• If you’re open, honest, and represented by someone who understands HMRC investigations, it can often end with a negotiated settlement — no criminal action, just a bill to pay.
• But if you try to hide information, delay responses, or deny obvious facts, it can quickly turn into a COP9 or criminal case.

Can a COP8 enquiry become a COP9 or criminal case?

Yes — and this is the main risk.

If HMRC starts under COP8 and later finds evidence of deliberate dishonesty or false declarations, they can upgrade the case to COP9 (civil fraud) or, in extreme cases, criminal investigation.

That’s why full cooperation is crucial. You don’t want to give HMRC the impression that you’re hiding something. Many advisers say, “Treat COP8 like it’s already COP9” — meaning, take it seriously from day one.

How should I respond if I receive a COP8 notice?

First — don’t panic, but don’t ignore it.

Here’s what to do:

• Get our specialists help immediately — we are tax investigation experts, not just a normal accountant.
• Do not contact HMRC yourself until you’ve had professional advice.
• Gather your records — bank statements, accounts, contracts, and anything related.
• Be honest with your adviser — they can only protect you if they know the full story.

Your adviser will typically contact HMRC on your behalf, ask what triggered the investigation, and manage all communications to avoid unnecessary escalation.

How long does a COP8 investigation take?

It can drag on — sometimes for months, sometimes years.

The speed depends on:

• How complex the case is.
• How quickly you and your adviser respond.
• How much information HMRC already has.

Most cases last between 12 to 24 months. The more cooperative and transparent you are, the faster it tends to resolve.

Important: Even if you respond quickly, HMRC will require full preparation of documents and detailed accounting records. Gathering and organising these records can take significant time, especially for historical years or complex structures.

Finally

A COP8 investigation doesn’t automatically mean wrongdoing, but it does signal that 

• HMRC wants to review your tax affairs — especially if there are big gaps in filings or missing declarations.
• How you handle it — calmly, professionally, and with our expert guidance — determines whether it stays a civil matter or escalates.
• If you’ve received a COP8 letter, act fast, stay transparent, and get our specialist help.

In Summary: