Which issue of NHSS 12D is current, and how to tell if your copy is out of date

The short answer

Issue 5 of the NHSS 12D scheme document was published in July 2025 and replaced Issue 4, which was dated December 2024. Issue 4 has been withdrawn and is no longer on Lantra's site. On 5 September 2026 Lantra's Schedule of Suppliers page listed Issue 5 as current and showed no Issue 6.

What changed in Issue 5

The one substantive change was the addition of the Gate Person, also called the Airlock Installer, as a defined role and as a mandatory training category for anyone who controls entry into or through a traffic management system. It brought 12D into line with the equivalent requirement in 12A/B. Beyond that, Issue 5 tidied the document by removing the old revision markers that had been carried since before 2018. If you want the detail on the Gate Person role and the two start dates that have been quoted for it, read our guide on the Gate Person requirement.

Issue 4, the December 2024 edition, was the bigger rewrite. Compared with the 2018 edition it introduced the UKAS CertCheck listing, controls on impact protection vehicles, near-miss analysis, a six-year record retention period and the requirement for two internal audit site visits a year by a person technically competent in 12D. If your copy predates December 2024 you are missing all of that, not just the Gate Person role.

Where the authoritative copy lives

The scheme document itself names Lantra's Schedule of Suppliers page as the place it is published, and National Highways' supplier pages say the same. That page is lantra.co.uk/national-highway-sector-schemes-nhss/schedule-of-suppliers/. Neither UKAS nor the National Highways standards site hosts scheme documents.

We do not host or mirror the PDF here, and we suggest you do not keep a copy on a shared drive as your working reference either. Keep a link to the Lantra page, and record in your document register which issue and date you last downloaded.

Why a search engine can hand you the wrong one

Training providers and consultancies have hosted copies of earlier issues over the years, and those copies still rank well in search results. The scheme document's own implementation notes warn about exactly this. A copy that arrives through a search result, an email attachment or a client's contract pack may be Issue 3 or Issue 4 and look perfectly official. The only safe check is the Lantra page.

How to tell whether your copy is out of date

1. Open the front page of the copy you hold. The issue number and month are printed there. Anything other than Issue 5, July 2025, is superseded.
2. Open Lantra's Schedule of Suppliers page and compare. If Lantra lists a later issue, yours is out of date whatever it says on the front.
3. Check your document register. It should name the issue, the date and where the copy came from, and it should show when someone last checked the Lantra page.
4. Look at anything you have derived from the scheme document: your quality manual, your training matrix, your internal audit checklist. If they were written to Issue 4, they will not mention the Gate Person category.

How often the document changes

The Sector Scheme Advisory Committee reviews the scheme document at least once a year and the document describes itself as live, which means users are expected to hold the current version. Issues do not come out on a fixed cycle: the 2018 edition stood for six years, then Issue 4 and Issue 5 came seven months apart. When a new issue appears, the implementation notes allow a visit falling within two months of publication to be assessed against the previous edition, and give organisations up to fourteen months to move across. Your certification body will tell you which edition a particular visit is assessed against.

A note on ISO 9001

The scheme document is written against ISO 9001:2015, and certification bodies assess 12D against that edition until the advisory committee revises the document. ISO 9001:2026 is scheduled for publication on 16 September 2026. When it appears, nothing changes in 12D on that day; watch the Lantra page for a revised issue and your certification body for its transition arrangements.

What we check, and when

We look at the Lantra Schedule of Suppliers page and the NHSS news page every month and update the date at the top of this guide. If you find a later issue before we do, please tell us at info@denverhouse.co.uk.

SchemeReady's question bank is written against Issue 5 (July 2025) and prints the bank version on every report; see pricing if you want to check your own evidence against it.