Wilmot Breeden locks and (Union) keys.


Jaguar used Wilmot-Breeden locks and barrels on all their XK types. Wilmot-Breeden keys are branded “Union”. The following gives an overview of the history of Wilmot-Breeden and the details of the applied barrel versions for the Jaguar XK (140).


Starting in 1932, Ford UK began to use “MRN” series keys, which has codes ranging from 01 to 50.  Other car brands also applied Wilmot Breeden locking systems. Jaguar in the post-war era, was one of them. These codes were used through 1949, but as automotive production increased, they needed more codes to go around. Jaguar applied the FNR series as well, in addition to the MRN.

Beginning 1949 the “FA” code was introduced, which features codes from 501-625. These codes were widely used from 1949 until August 1959.

In November 1955, another key code appeared, this time a “FP” code, which saw numbers ranging from 626-750.

Key codes can be found either on the face of the ignition switch, stem of the door handle, or on the lock barrel itself. However, barrels, door handles or even ignition switches, could have been changed to another key code at any time.

Original keys were made by Union / Wilmot Breeden.

There are many different locking barrels used: separate versions exist for door, ignition, boot lid, petrol lid and glove box. Each of these barrels is different in length and overall design, but they do (or may) share the same keys.

Wilmot Breeden Key codes and Year of introduction

  • 1932      MRN 01 through MRN 50
  • 1945?    FNR 01 through FNR 25 (unique Jaguar?)
  • 1949      FA 501 through FA 625
  • 1955      FP 626 through FP 750
  •               FR 751 through FR 875
  • 1960?    FS 876 through FS 955
  •               FK 876 through FK 955
  •               FT 101 through FT 225
  •               NH 2001 through NH 3000
  •               FR 01 through FR 1080
  •               EJR 01 through 50

image   Profiles of various key types

The barrel numbers are shown on the face of the ignition switch on early cars. The numbers were also stamped on the glove box housing, and the boot handle stem. On later cars, the original owner received a metal tag with the key number and the number was no longer stamped on the ignition switch housing to prevent that a spare key could be easily cut.

Survey of Wilmot Breeden locking barrels for XKs

Wilmot Breeden XK locks

Wilmot Breeden locking barrels for Jaguar XK 140 FHC

image image

Ignition lock barrel                          Door & Boot lock barrel

image image

Petrol filler lid lock barrel               Cubby box lock barrel

Door locks set for XK 140 new                                                                        New locks by Weston Body Hardware (Left to Right): Petrol filler, 2 x Door/boot, Ignition

Key numbers and types for Jaguar XK 140

  • Door lock           FA round head
  • Petrol filler         FA round head
  • Ignition lock       FA round head
  • Boot lock           FNR rectangular head
  • Cubby box         FNR rectangular head

 Examples of Wilmot Breeden Keys

  • Top Left:         FA & FNR Round
  • Top Right:       FA Rectangular head shape
  • Bottom Left:    FP Round left
  • Bottom Right:  FP Rectangular head shape.


Wilmot Breeden lock barrel principle

Every lock consists of 5 brass tongues composed of three different dimensions, corresponding to the cuts made in the key. A deep cut in the key corresponds with a higher remaining part in the tongue (see photo below). The overall distance over the 5 tongues is 3/8 “ meaning each tongue is spaced at 5/32” from the other.

image Example: Ignition lock FS 899

High     Low    Low      High     High

Jaguar glove box lock

Jaguar glove box lock with key code number stamped on the base of the lock.

image Key of “cubby” box always has a rectangular head

One thought on “Wilmot Breeden locks and (Union) keys.

  1. Bud Marston

    Excellent summary of Wilmot Breeden history and description of key codes.
    I am writing a book on vintage Jaguar keyrings and hope to include several pages of very general information on Wilmot Breeden.
    Question: Would you permit me to use the information on this webpage? I would rearrange it but probably keep most of it in tact as written. Of course I would provide full credit to the individual that crafted this fine Wilmot Breeden text!
    Please let me know either way!!


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