GUIDE
Great Britain did not inherit the MDR. It kept the Medical Devices Regulations 2002, which carry the old directive across almost unchanged — eighteen rules, not twenty-two, and no Rule 11 for software. Anyone who learned classification on the Regulation will get Great Britain wrong in a predictable direction.
Written with Francesca Di Giuseppe, Senior QA/RA Specialist (LinkedIn)
Under review by Francesca Di Giuseppe, Senior QA/RA Specialist — this guide has not yet been through that review.
The UK Medical Devices Regulations 2002 implemented Directive 93/42/EEC. When the United Kingdom left the European Union those regulations were retained, and the MDR — which applied from May 2021 — was never adopted in Great Britain. The practical effect is that Great Britain classifies devices under a framework the European Union has replaced.
So the divergence is not a matter of drafting differences at the margin. It is a whole regulatory generation: eighteen classification rules where the MDR has twenty-two, and none of the changes the Regulation made to how devices are classified.
Under the Windsor Framework, Northern Ireland remains aligned with EU rules. The MDR applies there and CE marking is the relevant route. Everything in this guide concerns Great Britain — England, Wales and Scotland. Treating “the UK” as one market is the first mistake, and it is made in slide decks constantly.
| SUBJECT | GREAT BRITAIN | EUROPEAN UNION |
|---|---|---|
| Instrument | UK MDR 2002, Annex IX — 18 rules | MDR 2017/745, Annex VIII — 22 rules |
| Software | No dedicated rule. Classified on the general rules, or with the device it drives. | Rule 11, which moved most standalone software from Class I to IIa or above. |
| Substance-based devices | No counterpart to Rule 21. | Rule 21 classifies by site of action and absorption, up to Class III. |
| Nanomaterials | No counterpart to Rule 19. | Rule 19 classifies by potential for internal exposure. |
| Active implantables | A separate directive-era regime rather than a classification rule. | Brought inside Rule 8 as Class III. |
| Mark | UKCA, with transitional acceptance of CE marking | CE |
NOTE —
Rule 11 was the MDR's most consequential classification change. It reclassified standalone software wholesale: a product that was Class I under the directive is routinely Class IIa, and can be IIb or III where a wrong output could cause serious harm or death.
Great Britain has no Rule 11. The same software, with the same intended purpose, is classified under the general rules — commonly ending at Class I where the EU puts it at IIa. Two conformity assessment routes, two sets of evidence, one product.
A lower class is not a lighter product. The essential requirements of the directive still apply, clinical evaluation still applies, and the MHRA has been explicit that it intends to modernise the framework. Building a British regulatory position on the current gap is building on something that is announced to change.
CE marked devices continue to be accepted in Great Britain on a transitional basis, with different end dates depending on which European instrument the device was certified under — directive-certified devices and MDR-certified devices are treated differently, and certificate expiry can end the transition sooner than the calendar date. In February 2026 the MHRA opened a consultation on recognising CE marking indefinitely.
NOTE —
Anyone who learned classification on the MDR will get Great Britain wrong in a predictable direction: they will apply a rule that does not exist there. Rule 11, Rule 19, Rule 21 and Rule 22 have no British counterpart, and reaching for them produces a class the UK MDR 2002 does not support.
The reverse error is rarer and more expensive: assuming the British class carries to Europe. It does not, and for software it usually understates the European class by at least one step.
NOTE —
