Are big cats on the loose in Britain?

Apparently the UK is over-run with lions, tigers, pumas and the like. Can John master animal tracking skills to catch one alive or will Mike's theory that pop star Rod Stewart's 70s lifestyle is to blame put an end to speculation. With permission from an eyewitness farmer in North Wales, the Unexplainers set up a big cat watch nerve centre, but will a trap set with offal and a trail camera reap rewards?