Delete purchased items on iphone?

I brought 3 tv programs on my iphone 4s a while back, it isn't letting me delete them, how do i delete them as i don't need or watch them anymore? Ps i have ios 7

Maybe you'll have to do it on the computer then sync with your phone? I'm just speculating since i've never bought anything on itunes…

Hook the phone up to the computer… Go into the iTunes app on the computer the phone will then take a little while to sort itself out and then you are ready.
Now go into the video tab at the top of the page and uncheck the videos you no longer want on your device.
Once this is all done click on the tab to sync the phone and the sync process will be done and this time because you unchecked the videos they will be removed from the device but will remain you're property because you have purchased them with your money, so if you ever want them back all you have to do is the same procedure but this time check the videos and they will be synced back onto the device.

If you can't select and delete from the iPhone,
go to iTunes and delete 'from the Phone tab' on iTunes and sync to iTunes