Changing the Locks When You Move into a New Home

When you complete on a property purchase or sign a tenancy agreement, the keys handed to you represent only the ones the seller or landlord knows about. Over the lifetime of a home, keys get cut for cleaners, dog walkers, relatives, tradespeople, and previous tenants — and those copies rarely get collected back in. There is no ill intent assumed here; it is simply the reality of how homes are lived in. What matters is that from the moment you take possession, you have no way of knowing how many copies of your key exist or where they are.

A door lock replacement London homeowners often treat as optional is, in practice, one of the most cost-effective security steps you can take. Many home contents insurers also quietly expect it — some policies include a clause that the locks must be of a certain standard or that you must be the only keyholder. Fitting a new cylinder or a new lock set on day one means you start with a clean slate, a known number of keys, and the right hardware for your insurer's requirements. It is a straightforward job for an experienced locksmith and, in most cases, is completed within the hour.

The majority of homes in Hackney built or refurbished since the mid-1990s have uPVC or composite front doors. These use a multipoint locking system operated by lifting the handle and turning the key, and at the heart of that system is a euro cylinder — the oval-shaped barrel you insert your key into. The critical thing to understand is that standard euro cylinders are vulnerable to a technique called cylinder snapping, where an intruder uses brute force to snap the cylinder in two and gain entry in seconds. This is not a rare edge-case; it has been a documented problem across London for years and is precisely why the industry developed anti-snap cylinders.

When we carry out a uPVC door lock repair London call or a straightforward cylinder upgrade, we fit anti-snap, anti-pick, anti-drill cylinders that meet the TS007 3-star rating — the benchmark that most insurers and the Secured by Design scheme recognise. The cylinder itself is replaced; the multipoint mechanism in the door body is usually left in place unless it is faulty. The job involves removing two screws and a small retaining bolt, withdrawing the old cylinder, and fitting the new one to the correct length for your door. It sounds simple, and in experienced hands it is — but getting the cylinder length wrong can leave the mechanism exposed or the door refusing to lock properly, which is why a trained locksmith is always the right choice for this work.

Older timber front doors — common in Hackney's stock of Victorian and Edwardian terraces, particularly around Dalston, Stoke Newington, and De Beauvoir Town — typically have two locks: a Yale-type nightlatch (the one that snaps shut when you pull the door closed) and a 5-lever mortice deadlock fitted into the edge of the door. The nightlatch handles day-to-day convenience; the mortice deadlock is the serious security lock you use when leaving for the day or going to bed. For full insurance compliance, both should meet current standards — and the mortice lock specifically should carry the BS3621 kitemark, which is what most home insurers specify.

Changing the locks on a timber door involves two separate operations. Replacing the nightlatch cylinder is straightforward — the cylinder is usually held in place by a single screw on the interior rose. Installing or replacing a mortice deadlock is a slightly more involved piece of work: the lock case sits in a mortice pocket cut into the door edge, and the striker plate is recessed into the door frame. If you are keeping the same size of lock, the existing pockets should accept the new hardware directly. If you are upgrading to a larger or different profile lock — for example, learning how to install a mortice lock in a new door, or in a door that previously had only a nightlatch — the locksmith will need to cut or extend the mortice pocket, which adds a little time but is a routine part of the job. The result is a door that meets insurer expectations and is significantly harder to force, pick, or bump.

Moving day is chaotic, and lockouts happen precisely when hands are full and attention is stretched thin. If you find yourself locked out of your house — key left inside, lock unfamiliar, door pulled shut in error — the first sensible steps are the same in any situation: check whether any other door or window is accessible from the outside (ground-floor flat with a rear garden gate left open, for instance), and check whether a family member or the estate agent still holds a key. Do not attempt to force entry yourself; damaged door frames and broken locks can cost significantly more to repair than a call-out, and there is a real risk of causing structural damage to the door.

What to do when you are locked out of your house ultimately comes down to one practical answer: call a professional locksmith. A skilled locksmith can open a locked nightlatch or euro cylinder lock without damaging the door — and can then, in the same visit, fit a new cylinder so the problem does not recur. At Dalston Locksmith we cover Hackney and the surrounding areas as a 24 hour locksmith London team, so whether it is 2pm on a Tuesday or 2am on a bank holiday, we send a locksmith straight away and are usually with you in around 30 minutes. Call 020 3757 8288 and we will confirm an exact price before we set off — no surprises on the invoice.

Not every door needs the same solution, and the right advice depends on what you have. For a uPVC or composite door, the priority is a TS007 3-star anti-snap euro cylinder in the correct length — measure from the centre of the fixing hole to each end of the cylinder before ordering, or simply let us measure on arrival. For a timber front door, the combination of a BS3621-compliant 5-lever mortice deadlock and a good-quality nightlatch covers most insurer requirements. For flats, remember that the communal entrance door is typically the responsibility of the freeholder or managing agent, but your own front door is yours to secure, and fitting a solid deadlock on a flat's internal front door adds a meaningful extra layer.

One question that comes up regularly is whether you need to change the cylinder a new lock or replace it entirely. In the UK context — where we talk about changing the cylinder rather than changing the cylinders — the answer depends on the age and quality of the existing hardware. If the lock mechanism itself is worn, damaged, or simply does not meet current standards, full replacement is the right call. If the lock body is in good condition and you simply want to ensure no old keys work, a cylinder swap achieves that cleanly and at a lower cost of parts. Our team will assess what is on your door and give you an honest recommendation rather than defaulting to the most expensive option. As a trusted emergency locksmith London residents call day and night, we are built on repeat business and word of mouth — straightforward advice is how we operate.