How can I fix boot lock on peugeot 306 1996 (non central). ?

I have closed the boot and locked it. Now the key will not turn either way to lock or unlock, so it is now constantly unlocked and just needs the button to be depressed for the thieves to gain access. Do I have to take the lock off from the inside? If so, is it the two or so screws? Thanks if you can help.