BS3621 Mortice Locks - York Security

British Standard Insurance Rated Mortice Locks

BS3621 is the British Standard for thief resistant locks on external doors, and it is the lock specification most UK home insurers write into their policies. This collection brings together every York Security BS3621 kitemarked 5 lever mortice lock from M.Marcus, in both sash lock and deadlock versions.

Sash lock or deadlock?

• 5 lever sash lock - latch and key-operated bolt in one case, used with lever lock handles on back doors and single entrance doors
• 5 lever deadlock - key-operated bolt only, usually fitted with a night latch on front doors

How to spot a genuine BS3621 lock

Look for the Kitemark and the BS3621 reference stamped on the faceplate. Insurers may ask you to confirm this, so it is worth checking before you replace a lock.

Why York Security?

Unlike plain contract locks, York Security locks come in finishes to match Heritage Brass door furniture, including Antique Brass, Polished Brass and Satin Chrome, so the door edge looks as good as the handles.

Browse the full M.Marcus locks and latches, or compare mortice sash locks and mortice deadlocks from every brand.

Related collections

Looking for something slightly different? Explore these related M.Marcus and York Security ranges:

• BS3621 5 lever sash locks - insurance rated sash locks for external doors
• British Standard 5 lever deadlocks - key-only deadlocks for front doors
• York night latches - 40mm and 60mm rim night latches

Why buy M.Marcus locks from Trade Door Handles?

Trade Door Handles is run by T.H. Wiggans Ironmongery, an independent ironmonger trading since 1976, with a trade counter team that has specified locks, latches and door furniture for joiners, builders and homeowners for decades. M.Marcus has manufactured door hardware in the West Midlands since 1940, holds ISO 9001:2015 quality accreditation and is a member of the Guild of Architectural Ironmongers and the Master Locksmiths Association. If you are unsure which lock body suits your door or handles, contact us before you order and we will check the backset, centres and finish for you.