ITV already owns the rights to the third season of Supernatural, but when they treat second season this badly, who knows whether they will even show the third? But by owning the rights to it, they prevent anyone else from showing it instead.
If anyone wants to help, please e-mail ITV and ask them to continue showing Supernatual, urge them to give it a better timeslot and ask whether they plan to show season 3. The e-mail address is firstname.lastname@example.org. And please re-post this anywhere you can.