Locate the Emergency Trunk Release: Inside your Jaguar XJ8, look in the glove box for a small release lever marked with a trunk icon or something similar. Some models may also have a release button in the center console or near the driver's seat.
Pull the Release Lever or Press the Button: Once you've found the release, firmly pull the lever or press the button. This should disengage the trunk lock, allowing you to open the trunk.
Open the Trunk: Once the lock is disengaged, use the exterior trunk handle to open the trunk lid.
If there's no emergency trunk release inside the car, or it's not working properly, you may want to consult a professional locksmith or your Jaguar dealership to explore alternative methods of opening the trunk.