can i unlock telus iphone 5 to use here in the Uk

Hi all. I have a problem with my iphone 5.

I bought it from a small shop in Canada and on my return to the UK I found the phone to be locked on Telus network.

Can it be unlocked so I can use a UK network?

It would be a shame if I wasted my money on a none usable iphone.

Thanks in advance for any help.