Work Visa...Do I have to stay with that company?

Lets just say for arguments sake that I am sponsored by a company to come over and work. I now have a work visa. Does that work visa apply only to that particular job, or if that doesn't work out, can I stay over and find something else on the same visa?
I am sure I read something one way or another, but thought someone may be able to help me out?!
Thanks!

      Try this link, it seems to pertain to your question:
http://www.workingintheuk.gov.uk/working_in_the_uk/en/homepage/work_permits/overview_of_process/new3.html?