Jammed/Broken one way entry mortise lock

[AnnieMalec]

Hi,

I have a one way entry back door which has been a bit sticky since moving in and has now finally decided to completely jam. I'm a complete dummy with DIY and no clue what to do!

I've attached pics below.... Thanks in advance for any advice!

Album link is http://www.diynot.com/network/AnnieMalec/albums/

 

[Burnerman]

If a good soaking in WD40 doesn't yield any results (depending on whats wrong with the lock) I'd get someone with an angle grinder fitted with a 1mm thick slitting disc to cut the lock tongue away from the inside.......5 mins graft and the doors open.
John

 

[foxhole]

Has the door jammed? or the lock. I suspect just the door swollen with damp weather. Unlock and give it a kick.Have your tried key from both sides? If lock sticks you will need to lean on it while turning the key.