Two problems related to brake light have been reported for the 1998 Jaguar XJ8. The most recently reported issues are listed below.
The rear window mounted brake light fixture overheated and melted. It appears that the heat generated by the 5 bulbs in the fixture is above the melting point of the plastic material. In this case the bulb burned out before a fire started.
The entire rear brake lighting assembly, which is made of plastic, melted because the brake light bulb was too hot.