The Jaguar XK is a 2-door convertible sports car manufactured by British company Jaguar.
James Lester owned a Jaguar XK. Once he got stuck in roadworks on a motorway, somewhere near the Giant Burrowing Insect incursion. As none of the workers were working, Lester yelled at them from his Jag. (Episode 5.1).
The Jag apparently cost Lester "a fortune", so he was horrified when an Anomaly opened in the ARC's car park. He obtained an EMD and descended to the car park, claiming that this time it was personal. There, he found a Tree Creeper curiously examining his XK. He yelled at it angrily, asking if it had any concept of how much the vehicle cost before shooting it with his EMD, the multiple shots flung the creature over the car bonnet, rocking it slightly. (Episode 5.5)