Fiber wrapped Spark plug wires used on early Jags?

While testing my plug wires in a semi dark garage I noticed the 7mm Packard 440 copper core ignition wires were leaking (spark mid cable to head.) There must be some cracks in the insulation of these older wires.

Was fiber covered plug wire (various colors) used on the early (1950’s) Jaguars? I have only seen 1 engine that had this type of spark plug wire.


'56 Mk 1

Probably not as Jaguar tended to use the cheapest alternative available, but they look pretty cool.

As the wire is thicker you can see that they have made a custom wire conduit out of metal tube.