iPhone 4 16gb locked to Orange network ?

Hi I have this IPhone 4 16 go for sale... It is 1year old and works perfectly. No marks on the phone still looks brand new. I am selling it because I have an IPhone 5 now . I have the box with charger. If interested please phone me on 07870929179 or 07805611250 Cash on collection only. No time wastes.