Bird Helppppp! help NEEDED.?

We came home and noticed a magpie (we think its a magpie) in our back garden and we think it may be hurt, it wont fly, well hardly gets off the floor and it just stays there when we go near it, it gets scared and runs a bit if we try to pick it up or touch it though. we have rang the RSPCA but they said to wait for an hour, but i think it may have been there all day because my neighbour told me a local cat was chasing a bird in our garden this morning, but when i checked i didnt see anything. I dont think waiting an hour is the best thing to do and i think i can see a small scratch womb on its neck, i cant just leave it there in the rain, hurt... What can i do?! Please help!!! thnks ;)