Custom-made medical devices in the UK: rules, registration and Northern Ireland deadlines

1. Key takeaways

Custom-made devices are the only clearly stated exception in the British transition arrangements: custom-made devices compliant with EU MDD or AIMDD can no longer be placed on the Great Britain market. Instead, custom-made devices must discharge their obligations under the relevant part of the UK MDR 2002 and complete MHRA registration after being placed on the Great Britain market (reg 19 and reg 21B). In Northern Ireland, a custom-made device must be registered with the MHRA within 28 days of being placed on the market (SI 2021/905 reg 7(2)(a)).

The exception cuts both ways. On one hand, custom-made devices never benefited from the CE transition corridors, so there is no certificate-based runway to manage. On the other, they carry direct, immediate registration duties that begin at the moment of placing, with a fixed clock in Northern Ireland. Manufacturers of custom-made devices therefore face a compliance model that is simpler to describe but less forgiving to operate, because every individual placement event starts an individual deadline, and unlike batch-supplied products there is no stock buffer between manufacture and market.

2. Legal basis

• UK MDR 2002 (SI 2002/618, as amended): reg 15 (procedure for custom-made general devices), reg 28 (procedure for custom-made active implantable devices), reg 19 (registration of custom-made general devices), reg 21B (registration of custom-made active implantable devices).
• SI 2023/627 reg 4: reg 1ZA(1) makes clear that the expiry of reg 19B and reg 30A does not apply to custom-made devices (the explanatory note records that the periods for reg 19B and reg 30A were extended except in relation to custom-made devices).
• The Medical Devices (Northern Ireland Protocol) Regulations 2021 (SI 2021/905): reg 7(1) and (2)(a) (the 28-day registration deadline), reg 7(5) (fees, adjusted by SI 2026/197 reg 5(2)(a) to £300).
• Official guidance: the GOV.UK document titled ‘Timelines for acceptance of CE marked medical devices in Great Britain (GB)’.

3. Expert insights

Insight one: custom-made devices have their own procedure provisions in each part. Reg 15 (general devices) and reg 28 (active implantable devices) set out the conformity assessment procedures for custom-made devices, kept separate from the ordinary procedures in reg 13 and reg 27. This means custom-made devices have no default channel of self-declaration and nothing else: they must follow their dedicated procedure, with its own statement and documentation set. Teams that process custom-made devices through the ordinary procedure templates will produce declarations that do not match the applicable regulation, which surfaces later as a finding in audits and registration checks.

Insight two: the registration provisions are separated from the ordinary ones. For general devices, routine registration runs through reg 7A while custom-made registration runs through reg 19; for active implantable devices, routine registration runs through reg 21A while custom-made registration runs through reg 21B. Selecting the wrong provision when filing in DORS causes the registration information to diverge from the actual obligations, an error that is easy to make and slow to unwind once records are tied to the wrong legal basis. The distinction should be encoded in the registration SOP rather than left to the memory of the person doing the filing.

Insight three: in Northern Ireland, custom-made devices are the last territory of MHRA registration. From 28 May 2026, non-custom devices in Northern Ireland moved to EUDAMED registration and MHRA registration ceased to be required for them; however, custom-made devices fall outside the scope of EUDAMED and must still be registered with the MHRA, within 28 days of placing. This makes custom-made devices one of the few categories that must be handled on both sides of the dual system at the same time, and the 28-day clock in Northern Ireland runs in parallel with the Great Britain registration duty, so two registers and two deadlines attach to the same physical placement.

The £300 fee figure deserves its own note in the planning file, since SI 2026/197 reg 5(2)(a) adjusted the Northern Ireland registration fee and the amount recurs per registration event rather than per product family. A custom-made workshop that places frequently in Northern Ireland should model the fee load on placement frequency, not on catalogue size, and the model should sit alongside the 28-day deadline tracking so that the cost and the compliance clock are managed from the same record rather than drifting into separate spreadsheets owned by different people.

4. Practical recommendations

GRZAN recommends that custom-made devices be managed in a separate file from the routine product lines, recording the applicable procedure provision, the registration provision, and the differing British and Northern Ireland deadlines. For companies supplying both territories, one DORS account can cover both markets (official guidance confirms a single account suffices), but the registration obligations must still be discharged separately for each market, so the shared account must not be read as a shared duty.

Because every custom-made placement starts its own clock, the internal process should capture the placing date as a controlled data point at the moment of dispatch, and the registration task should be generated automatically from it rather than relied upon from memory. Where a device is placed in both territories on the same day, the file should record both registrations with their respective provisions, so that an auditor can see at a glance that reg 19 or reg 21B was used for Great Britain and the 28-day Northern Ireland rule was met.

Finally, the statement and documentation set required by the dedicated procedures should be templated once and reused. Because custom-made devices are individually specified, teams often treat each device as a fresh drafting exercise, which produces inconsistent statements and slows registrations. A fixed template carrying the procedure reference, the specification of the device, the responsible person and the placing date keeps every registration uniform, shortens review time, and makes the growing registration history of the workshop legible to any successor auditor.

5. Verification checklist

• □ It has been confirmed that custom-made devices are outside the CE transition corridors
• □ The applicable procedure provision has been confirmed (reg 15 / reg 28)
• □ Great Britain registration has been completed under reg 19 / reg 21B
• □ Northern Ireland custom-made devices are planned for registration within 28 days of placing
• □ The DORS account has been confirmed as covering both GB and NI

Regulatory information verified as of 29 October 2026.

• Appointment of a UK responsible person (UKRP) and support for signing the letter of authorisation
• MHRA registration (DORS): end-to-end filing and account lifecycle management
• Device classification, GMDN code selection and annual registration fee estimates
• Dual-route design for Great Britain and Northern Ireland, including UK(NI) options
• Post-market surveillance (PMS) system build, PMSR/PSUR preparation and vigilance reporting
• Emergency handling of serious incidents and field safety corrective actions (FSCA)
• Monitoring of UK regulatory change and compliance gap assessments

GRZAN supports manufacturers entering the United Kingdom with UKCA registration pathways and classification strategy, from first route analysis through to registration and post-market obligations. For a structured review of your product portfolio, contact info@grzanglobal.com.