Keeping number going from o2 to o2

[y2viks]

I've got my current o2 phone which I want to cancel because i've found a better deal on a website which suits my needs.

That phone is on o2 also and when I went to the o2 shop they wouldn't match the deal because it was online.

Is there anyway I can transfer my current number from my existing o2 contract to another without having to any intermediate steps?

Thanks