Deadlock

A mortice deadlock is a key-operated lock designed to provide straightforward, reliable security. Fitted into a pocket (mortice) in the door edge, it throws a solid bolt into the frame when locked—making it a popular choice for front and back doors, side entrances and other areas where you want a dedicated security lock without a handle-operated latch.

If you’re choosing a deadlock for an external door, a 5 lever model is typically preferred for improved security and a more robust mechanism. For internal doors where privacy is the main requirement, a 3 lever deadlock can be a practical option. Many homeowners also use a mortice deadlock alongside a nightlatch or latch lock to create a strong two-lock setup for everyday use and extra peace of mind.

To ensure the right fit, measure the backset (from the door edge to the centre of the keyhole) and confirm the case size of your existing lock. Matching these measurements makes replacements simpler and helps keep any door alterations to a minimum. You can then choose the finish and any matching accessories to suit your door furniture.

Browse our selection of deadlocks to find the correct backset, case size and security level for your door—ideal for replacements, upgrades and refurbishment projects.