robs

Parked up today, went to switch off & pull the key, the key fell out. Thought something not quite here, & realised the engine still running...uh oh...
Now cannot turn the key into the lock position (though the engine can be switched off!). Have tried with the spare tonight & exactly the same. Tried some WD40 (without setting fire to the thing .... so far) but no improvement. Any suggestions?