Bird stuck in house

Sorry if this is the wrong forum or if I should contact RSPB/RSPCA directly, let me know if so.

I have a Magpie stuck in my house. He seemed fine but flew around when I walked in on him and might have hurt himself. He's currently sat still huddled in the corner of the room and not moving around but is aware and awake.

I've left open the window and closed off the door, i'm hoping to come back in an hour and see him gone, but if he isn't, what do I do?