Common Mistakes in UK Customs Declarations -And How to Avoid Them

UK customs procedures have changed significantly post-Brexit — and so have the risks. Today, a customs declaration isn’t just a formality. It’s a precision game, and even small errors can cause major delays, added costs, or even legal trouble.

Here’s your deep dive into the most common mistakes importers make — and how you can avoid them with confidence.

1. Incomplete or Inaccurate Documentation

Let’s start with the most common pitfall: documentation. Customs declarations rely heavily on supporting paperwork, and missing or incorrect information is the number one reason for delays.

What can go wrong?

• Missing Commercial Invoice
• Incorrect Incoterms
• Mistyped consignee information
• Currency errors or missing values
• Lack of packing list or weight mismatches

✔ Pro Tip
Every document you submit is a legal record. Treat it that way. Double-check all invoices and ensure consistency between documents. Even the postcode matters.

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Small errors in a customs declaration create big problems at the border.
But with the right support, there are no obstacles — only opportunities.

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2. Using the Wrong Tariff (HS) Code

HS codes are the DNA of your goods in the customs system. One wrong digit and you might be paying too much duty — or triggering a red flag.

Why it matters:

• Wrong HS codes can classify goods incorrectly
• Incorrect duty or VAT calculations
• Delays for goods that require licensing
• In some cases: seizures or investigations

How to avoid it:

Use the UK Trade Tariff Tool and match your products carefully. Consult with a customs intermediary when in doubt.

3. Declaring Without a Valid EORI Number

An EORI number is essential for importing into the UK. No EORI = no clearance. Simple as that.

Common mistakes:

• EORI number registered to wrong address
• Using a number that expired or was revoked
• Forgetting to add the number to the declaration

✔Pro Tip
Apply early — and keep your EORI number up to date with Companies House records.

4. Overlooking Import Licences and Product Restrictions

Certain goods — from food to chemicals to dual-use items — require special permissions to enter the UK.

Risk factors:

• Shipping restricted items without documentation
• Not checking if sanitary/phytosanitary controls apply
• Failing to notify port authorities in time

Solution:

Check the UK Strategic Export Control List, DEFRA, and TRACES NT if your product is agricultural, biological, or sensitive.

5. Submitting Declarations Too Late

Timing matters. Customs clearance isn’t just about what you submit — but when.

What delays do:

• Increase storage costs
• Disrupt supply chains
• Trigger late delivery penalties
• Damage supplier/buyer trust

✔ Pro Tip
Treat customs prep like packing your goods — it’s part of your logistics, not an afterthought. Set internal deadlines before departure, not after.

6. Using Inexperienced or Incomplete Intermediaries

Some brokers just submit forms. But true customs compliance is strategic. If your intermediary doesn’t ask the right questions, you’re flying blind.

Watch out for:

• Brokers who don’t explain your obligations
• Lack of help with licensing or documentation
• Errors in submission you have to chase later

Our approach:

At Customs Flow Declare, we act as your partner — not just a middleman. We educate, support, and execute — so you don’t get stuck.

Avoiding Mistakes Is a Competitive Advantage

Customs mistakes don’t just cost money — they damage your reputation. In the import/export world, reliability is currency.

The better way:

• Use verified HS codes
• Get your documentation aligned
• Partner with experts who actually care
• Build systems that make customs predictable, not painful

At Customs Flow Declare, we make your customs process smooth, reliable, and stress-free. We treat your business like our own — because we know what’s at stake.

Let’s turn customs into your competitive edge.

Mistakes cost more than fees — they cost momentum. Let’s make sure you never stop moving.‍