Bulldog Locksmiths


0757 2424 999 / 0845 004 9211

London / Slough / Reading / Wycombe / Watford

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0757 2424 999 / 0800 061 4075

London / Slough / Reading / Wycombe / Watford

Is your transponder key broken?

Most people don’t even realise they have a transponder key, but it’s likely that you do have one.

A transponder key is designed to stop vehicle theft by using a chip in the casing of the key.

This returns a code sent by the car’s electronic control module (ECM) when the ignition is on.


If the code returned by the chip in your transponder key is recognised by the car’s computer, it will turn off your car’s immobiliser and start the engine.  Therefore if someone to tries to cut a new key, they would still need the correct code to start the engine.

The experts at Bulldog Locksmiths provide a 24 hour on-site locksmith service to immediately help when:

  • You’ve lost or broken your transponder key and need a replacement
  • You require a duplicate key if you share the car or in the event you should lose the key
  • Your key no longer works with your car and you need to re-programme or replace the key.

If you’re in the London, Heathrow, Slough, Reading,  or Watford area and need fast and efficient help with your transponder key, call the vehicle specialists at Bulldog Locksmiths on 0757 2424 999.

If you’ve lost your transponder key and need access to your car, for security reasons proof of vehicle ownership and photo ID is required.


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  • 'These guys are amazing, i lost my keys one night and was grateful enough to find bulldog locksmiths on the internet, my mercedes was opened without damaged and a key was programmed and ready to start my car on the roadside. Exceptional service and affordable. Thanks Bulldog.'

    Raj Nahar, West London
Areas & Postcodes We Cover
  • London - EC1 - EC4, WC1 - WC2, E1 - E18, SE1 - SE28, SW1 - SW20, W1 - W14, NW1 - NW11 & N1 - N22
  • Slough - SL0, SL1, SL2, SL3, SL4, SL5, SL6, SL7, SL8, SL9, SL60 & SL95
  • Reading - RG1, RG2, RG4, RG5, RG6, RG7, RG8, RG9, RG10, RG12, RG14, RG17, RG18, RG19, RG20, RG21, RG22, RG23, RG24, RG25, RG26, RG27, RG28, RG29, RG30, RG31, RG40, RG41, RG42 & RG45
  • Wycombe - HP1, HP2, HP3, HP4, HP5, HP6, HP7, HP8, HP9, HP10, HP11, HP12, HP13, HP14, HP15, HP16, HP17, HP18, HP19, HP20, HP21, HP22, HP23 & HP27
  • Watford - WD3, WD4, WD5, WD6, WD7, WD17, WD18, WD19, WD23, WD24, WD25 & WD99