Lock guide

Everyone wants to make sure their home is secure, so it pays to give plenty of thought as to whether your house locks provide adequate protection.

There are several different types of house locks available, and some can help you save money on your insurance premiums.

Here, we look at the various kinds of locks on offer so that you can ensure your home is as safe as it can be when you are out and about.

Four main types of locks

Five-lever mortice deadlock

Mortice LockA mortice deadlock is one that requires a pocket, known as the mortice, to be cut into the door or wall into which the lock is to be fitted. The more levers a mortice lock has, the more secure it is.

As a result, insurers often insist that you must have a five-lever mortice lock conforming to BS3621 on all exit doors and key-operated locks on all ground floor and accessible windows to qualify for cover, although often the wording may vary slightly depending on the insurer.  The BS3621 indicates that the lock conforms to current British Standards.

Some insurers will offer you offer you a discount of up to 5% off your home contents insurance premiums if you have this kind of lock installed. Remember however, that the locks must have been in use if you want to make a successful claim.

For example, insurers are likely to refuse to pay out if burglars break in through a window that has been left open, regardless of whether you have the correct lock in place.

Multi-point locking system

A multi-point locking system has a minimum of three locking points that all lock simultaneously by the turn of a key.

Multi-point locks are most common on uPVC doors and, if they are a main entrance, then for insurance purposes you will need a lock cylinder with at least five pins. 

The Master Locksmiths Association recommends the use of SS312 Diamond approved cylinders as these have been tested fully against all known methods burglars use to disable locks and break in.


NightlatchRather than being morticed into a door, a nightlatch is actually mounted onto the door.

These are much less secure than mortice locks, but can be used as an additional security measure. Double-locking nightlatches are the most secure type of nightlatch as they have a keyhole on the handle inside the door so that the latch can be deadlocked from inside.

Always look for a nightlatch which conforms to British Standards to ensure a high level of security.

Key operated window locks

Window LockIdeally you should have key-operated window locks on all downstairs windows. These are either fitted to the top or bottom of a window, or on the handle that closes the window.

Why security pays

Although installing locks can be expensive, over a long-term period you should be able to recoup some of the costs through lower insurance premiums. Remember too that having effective security measures in place will be a major deterrent to burglars, therefore making your home a safer place to live.

When taking out home insurance, always check to see what the minimum standards of security required are - failing to have them in place could invalidate your cover and mean your claim is refused if you do fall victim to burglars.

Page last updated: 19 January 2016