If i hand in a blocked iPhone to the Apple store what will they do?

Me and my friend found an iPhone 5 in the bus and it was turned off because it was out of charge so we took it with us and charged it after charging it we noticed the phone was blocked because it say "no service" the phone is on o2 as we checked on settings we're not sure what to do with it sell it for parts because its usless or give it to the Apple store. I'm just curiouse what they will actually do to the iPhone since its blocked and useless?

I'm not sure what they will do, but if there are contacts on the phone such as "mom" or "dad", you may want to contact them. Otherwise iphone 5's sell for parts as high as 400$

That phone actually belongs to somebody! It might be the original owner, or it might be the insurance company that paid out for the loss. Hand it in. Try to sell it and it might bite back. They are traceable. Stealing by finding is a crime.