It can be changed by two thirds of Parliament.
UPDATE:
It seems the Tories want to try to regulate Guido:
“relevant publisher” means a person (other than a broadcaster) who publishes in the United Kingdom: a. a newspaper or magazine containing news-related material, or b. a website containing news-related material (whether or not related to a newspaper or magazine)”
@lisaocarroll Good luck with that.
— Guido Fawkes (@GuidoFawkes) February 12, 2013