The comparison
| UK REACH | EU REACH | |
|---|---|---|
| Territory | Great Britain — England, Scotland, Wales | EU/EEA, and Northern Ireland |
| Regulator | Health and Safety Executive, with the Environment Agency | European Chemicals Agency (ECHA) |
| Policy authority | Defra and the devolved administrations | European Commission and Member States |
| Submission system | Comply with UK REACH | REACH-IT |
| Registration threshold | 1 t/y per legal entity | 1 t/y per legal entity |
| Data sharing | No mandatory joint submission equivalent to the EU SIEF model | Mandatory data sharing and joint submission through substance information exchange |
| Transitional deadlines | 27 October 2029, 2030, 2031 | Passed — 2010, 2013, 2018 |
| Candidate list | GB candidate list, maintained by HSE | EU candidate list, maintained by ECHA |
| Authorisation list | GB authorisation list | Annex XIV |
| Restrictions | GB restriction list, diverging from Annex XVII over time | Annex XVII |
| Only Representative | Must be established in Great Britain | Must be established in the EU/EEA |
| Classification regime | GB CLP, with the GB mandatory classification list | EU CLP, with Annex VI harmonised classifications |
The three differences that cost money
1. There is no shared data pool
EU REACH is built on compulsory data sharing: registrants of the same substance must share data and submit jointly, which spreads the cost of studies across an industry. UK REACH has no equivalent compulsion. Access to the studies underpinning an EU dossier is a commercial negotiation, and the price is set by whoever owns them.
This is the single largest cost driver in UK REACH and the reason the government is designing the Alternative Transitional Registration model — an attempt to reduce the amount of full study data GB registrants must buy twice. Where the ATRm stands →
2. The lists are drifting apart
At exit, the GB and EU candidate, authorisation and restriction lists were identical. They are not identical now, and the gap widens with every independent decision on either side. A substance restricted in the EU may remain lawful in GB, and increasingly the reverse.
Practical consequence: you cannot run one watch list. A dual-market business must monitor both, and must accept that its GB and EU product portfolios may legitimately differ.
3. Northern Ireland sits on the other side of the line
Under the Windsor Framework, Northern Ireland applies EU REACH. A UK-wide business therefore straddles both regimes. Moving goods from NI into GB is an import for UK REACH; moving from GB into NI places goods on an EU REACH market. An EU Only Representative covers Northern Ireland but not Great Britain, and a GB one covers the reverse.
Your EU registration number has no legal effect in Great Britain
It is evidence that data exists. It is not market access. Unless the registration was brought across through grandfathering, GB market access requires a UK REACH registration held by a GB entity — your own, or an Only Representative's.
What a dual-market business has to run in parallel
- Two registrations per substance, in two systems, with two fee schedules.
- Two Only Representative appointments, if you manufacture outside both territories.
- Two classification positions, because the GB mandatory classification list and EU Annex VI diverge.
- Two safety data sheet variants, in the format each regime requires.
- Two regulatory watch processes for candidate list, authorisation and restriction changes.
- A clear internal rule for which entity imports what, since role determines duty in both regimes.
What can be reused
The underlying science does not change at the border. Study data, robust study summaries, read-across justifications, QSAR assessments and much of the chemical safety assessment can be carried from an EU dossier into a UK one — provided you hold the rights to use them. That last condition is where most reuse plans fail: a letter of access for EU REACH purposes does not automatically permit use in a UK REACH submission.
Check your data rights before you budget on the assumption of reuse. If the letter is silent on UK REACH, treat it as not covering UK REACH until the owner confirms otherwise in writing.
We run UK REACH, EU REACH and Turkish KKDIK dossiers for the same substances, which is why we tend to see the reuse question early. If you are placing material on more than one of those markets, the work should be sequenced once rather than commissioned three times — our sister practice ONAY Mühendislik covers the EU and Turkish side.
Comparison of UK REACH and EU REACH as they stand following the extension of GB transitional deadlines to 2029–2031. Both regimes change; verify list entries against the current published versions.