Car key replacement in the UK. What it costs, who to use, and what to do next.
A complete guide to replacing your car key, from a basic cut key to a full keyless fob, plus the one step most people skip that leaves their new key just as vulnerable as the old one.
Not all car keys are the same. The type you have changes the cost significantly.
Before you call anyone, it helps to know which type of key your car uses. Here are the four main categories and what replacement typically costs in the UK as of 2026. All prices are indicative ranges from a mobile locksmith. Dealer prices are generally higher.
Basic cut key
Older vehicles with no transponder chip. A locksmith can cut this quickly from a blank. No programming needed.
Transponder key
Has a chip inside that communicates with the car’s immobiliser. Needs to be both cut and programmed to your specific vehicle.
Remote key fob
Combines a cut key with a remote locking button. Needs programming. Common on vehicles from 2005 onwards.
Keyless smart key
No physical key needed to start the car. Purely electronic. Programming is more complex and parts can be expensive, especially for premium brands.
Which option is right for your situation?
Both routes can replace your car key but they differ on cost, speed, and convenience. Here is a direct comparison.
| Factor | Mobile Locksmith | Main Dealer |
|---|---|---|
| Comes to you | Yes, usually within hours | No, you go to them |
| Cost | Generally lower | Generally higher |
| Speed | Same day in most cases | Can take several days |
| OEM parts guaranteed | Not always | Yes |
| Covers all key types | Most modern locksmiths can | Yes |
| Warranty on work | Varies by provider | Usually included |
For most people, a qualified mobile locksmith is the fastest and most cost-effective route. Look for MLA registration at masterlocksmith.co.uk. For warranty vehicles or complex keyless systems on premium cars, your main dealer may be worth the extra cost for peace of mind.
A new key gets you mobile again. It does not make your car harder to steal.
Here is something worth thinking about once your replacement key is sorted. The way most cars are stolen today has nothing to do with whether a thief has your key or not.
A relay attack uses a device to amplify your key fob’s signal from inside your house, even through walls and doors. It tricks your car into thinking the key is present, unlocks it, and starts the engine. The whole process takes under 60 seconds and leaves no trace. Your brand new key broadcasts exactly the same type of signal as the old one. The relay attack works just the same.
The same is true of key cloning. If your old key was ever copied without your knowledge, a new key does not cancel it out unless you have the old key deactivated through your dealer. And even then, a cloned or relay-boosted signal bypasses standard factory security entirely.
A replacement key solves a logistical problem. A physical immobiliser solves a security problem. When the engine circuit is cut at the relay level, completely separate from your key system and your car’s electronics, relay attacks and key cloning have nothing to work with. The car will not start.
We add the protection a new key cannot give you.
Our relay-based immobilisers physically cut the engine circuit, independently of your key, your fob, and your car’s electronics. We design and build every device in the UK and come to your door to fit it. No ECU interference, no middlemen, one direct contact.
IC3ST, fitted
Standalone wireless immobiliser. Proximity TAG, app control, motion detection.
IS357, fitted
5m proximity detection, smartwatch support, Bluetooth and Wi-Fi app.
ONE Plus, fitted
4G remote, live camera, GPS, night auto-immobilise, Face ID.
Not sure which?
Take our quiz for a personalised recommendation based on your vehicle.
Things people ask when getting a key replaced.
Do I need to deactivate my old key if I get a replacement?
If your old key was lost or stolen and there is any chance someone else has it, yes. Ask your dealer or locksmith to remove the old key from your vehicle’s system so it no longer works. This is called rekeying or key deletion and is available for most modern vehicles.
Can my insurance cover the cost of a replacement key?
Many comprehensive car insurance policies include some cover for lost or stolen keys. Check your policy documents first before paying out of pocket. If your keys were stolen, you will usually need to report it to the police and get a crime reference number before making a claim.
How do I know which type of key my car uses?
If you can start your car without inserting a key, you have a keyless smart key. If your key has buttons for locking and unlocking but you still insert it to start, you have a remote fob. If there are no buttons at all, it is likely a basic transponder key. When in doubt, your vehicle’s handbook or a quick search of your make, model, and year will confirm it.
Will a LockCar immobiliser work with my new key?
Yes. Our system is completely independent of your key and your car’s electronics. It does not matter what type of key you have or whether you have just had one replaced. The immobiliser works at the engine circuit level and is not affected by anything related to your keys.
How quickly can you fit an immobiliser after I get my new key?
In most cases we can book within a few days. Send us a WhatsApp with your vehicle and location and we will confirm availability straight away. Most installations take under an hour at a time and place that suits you.
New key sorted? Now let’s make sure it stays in your hands.
Take the 60-second quiz to find out which immobiliser is right for your vehicle. We come to you anywhere in the UK.