TRE vs MSS vs CDS Data: What UK Importers Need to Know

TRE, MSS and CDS data are three views of the same thing: your UK customs declarations. MSS was HMRC's legacy summary report, CDS is the live system where declarations are lodged, and the Trader Records Extract (TRE) is the downloadable, line-level history of every declaration made against your EORI number.

If you have been requesting MSS data from HMRC, you are using a format that has been replaced. TRE supersedes MSS with declaration-level detail, and that difference matters for every compliance review, post-clearance audit and duty reclaim you run. This guide defines each dataset, compares them directly, and explains when to use which.

What Are TRE, MSS and CDS Data?

The three terms describe different generations and formats of HMRC customs data. Two are current, one is legacy. Here is each in plain terms.

Trader Records Extract (TRE): the current standard

The Trader Records Extract (TRE) is HMRC's downloadable report of your full customs declaration history. Each row represents a single declaration line, mapped to the CDS declaration structure, covering imports and exports linked to your EORI number.

• Level of detail: line level. Every declaration line appears as its own row, with both header and item data.
• Typical fields: Movement Reference Number (MRN), 10-digit commodity codes, customs value, duty and VAT amounts, country of origin and dispatch, preference codes and Customs Procedure Codes (CPCs).
• Format: a CSV or similar tabular file, built for bulk analysis rather than on-screen browsing.
• Access: requested through Government Gateway. Files stay available for a 30-day download window before they must be re-requested.

For the request process step by step, read our guide on how to access your Trader Records Extract.

Monthly Statistical Statements (MSS): the legacy format

Monthly Statistical Statements (MSS) were summary-level customs data reports provided by HMRC. They showed aggregate import and export values by commodity code and country, but lacked declaration-level detail. You could see high-level trends, but not the specific lines, values or customs treatments behind them.

• Level of detail: summary only. Totals by commodity code and country, with no visibility of individual declaration lines.
• Source system: tied to CHIEF (Customs Handling of Import and Export Freight), the declaration system that CDS replaced.
• Status: retired. TRE supersedes MSS for traders who now declare through CDS.
• Use today: historical reference for periods before your business migrated to CDS.

CDS data: the live declaration record

The Customs Declaration Service (CDS) is HMRC's current system for lodging customs declarations. When people say "CDS data", they usually mean the individual declarations and statements visible through the CDS service on gov.uk.

• Level of detail: full detail, but viewed one declaration at a time.
• Where you see it: the CDS financial dashboard, declaration records, postponed import VAT statements and C79 certificates.
• Limitation: not designed for bulk review. Checking thousands of lines declaration by declaration is impractical.

How Do TRE, MSS and CDS Data Compare?

The simplest way to separate the three is by depth, breadth and purpose:

• Depth: MSS gave aggregates. CDS records and TRE both carry line-level detail, including values, codes and customs treatments.
• Breadth: CDS shows one declaration at a time. TRE brings your whole declaration history, often tens of thousands of lines, into a single structured file.
• Purpose: CDS is for lodging and checking individual entries. TRE is for analysis at scale. MSS served the analysis role in the CHIEF era, at summary level only.
• Currency: CDS is live. TRE is a periodic extract you request. MSS is closed and no longer produced for CDS declarants.

The shift from CHIEF to CDS is what drove this change in reporting. We cover the migration itself in MSS vs CDS data: what changed.

Why Did HMRC Replace MSS with TRE?

Because summary data cannot support modern compliance work. An MSS report could tell you that you imported a certain value under a commodity code from a given country. It could not tell you which declaration lines carried that value, what duty rate was applied, whether a preference was claimed, or which Customs Procedure Code was used.

Line-level TRE data answers all of those questions. That makes it possible to reconcile declarations against commercial records, test classification consistency, measure preference utilisation and identify overpaid duty on specific lines. None of that was possible from MSS summaries alone.

The timing follows the systems change. As declarations moved from CHIEF to CDS, HMRC's reporting moved with them, and the Trader Records Extract became the standard way for traders to obtain their own declaration history in bulk.

When Should You Use Each Data Source?

Each dataset still has a job. Matching the source to the task saves time and avoids gaps.

Use TRE data for audit and recovery work

Any exercise that needs your full declaration history should start with TRE:

• Post-clearance audit: review classification, valuation, origin and procedure codes across every line, not a sample.
• Duty reclaims: identify overpaid lines and evidence them for a C285 repayment claim to HMRC. See how to use TRE data for duty recovery and C285 reclaims.
• Preference reviews: find lines where a preferential duty rate was available under a trade agreement but full duty was paid.
• Import VAT reconciliation: match declared VAT amounts against your postponed import VAT statements and C79 certificates.
• Broker oversight: compare declaration quality and consistency across the agents filing on your behalf.

Use CDS records for day-to-day operations

The CDS dashboard remains the right place for operational tasks: checking the status of a single declaration, downloading monthly statements, resolving an entry error with your broker, or confirming what was lodged last week. It is current and authoritative, just not built for analysis across years of history.

Use MSS only for historical reference

If a question relates to periods before your migration to CDS, old MSS reports may be the only record you hold. Keep them archived, but do not build any current compliance process on them. They lack the detail HMRC itself now works from.

How Do You Request TRE Data?

The request runs through Government Gateway and takes a few working days to fulfil:

1. Log in to Government Gateway with the account linked to your EORI number.
2. Request your trade data through the customs services section, specifying the period you need.
3. Wait for HMRC to generate the extract, typically within 5-10 working days.
4. Download the file within 30 days. After that it expires and must be re-requested.

You can also authorise an agent, accountant or platform to retrieve the data on your behalf. Our guide to granting third-party access to your TRE data walks through the authorisation steps and how to revoke access later.

One practical reason to request the full history: HMRC can assess your declarations for three years after clearance, and the same window applies to reclaiming overpayments. A complete TRE covering that period shows you both sides of the ledger.

Key Takeaways for UK Importers

• MSS is the legacy, summary-level format from the CHIEF era. It has been replaced and should only be used for historical reference.
• CDS is the live declaration system. Use it for operational checks, statements and individual entries.
• TRE is the line-level extract of your full CDS declaration history. Use it for post-clearance audit, preference reviews, VAT reconciliation and duty reclaims.
• TRE files expire 30 days after HMRC generates them, so plan the download or authorise a third party to collect them automatically.

BorderAudit connects to Government Gateway, retrieves your TRE as soon as it is generated, and runs automated post-clearance audit checks across every declaration line. If you want to see what your data holds, check your audit eligibility in under a minute.