Mortise lock jammed shut

[WorriedDaughter1]

I have a door with a mortise lock that's jammed in the shut position. The lever handle isn't engaging with the mortise bit that goes into the strike plate. Fortunately I can get into the room another way, but it's not easy and I really need to get this undone.

I've unscrewed the plate with the handle and keyhole from the inside of the door. Both handle and spindle look fine. What else should I be doing? How can I retract the bit that's stuck in the doorframe? I've tried getting a bit of plastic around it to push it back, but the plastic isn't going through.

Any advice would be very welcome!

Turn the spindle with pliers? If it’s old a good squirt of WD40 may help loosen it first.

Thanks, AbbieFB. I've tried that, but turning the spindle isn't retracting the mortise for some reason. I've sprayed WD40 around with a liberal hand too.

Post some photos please. Also some photos of an identical one, from the door edge, on one of your other doors.

Do you have a set of screwdrivers?

You say "lock." Does it have a key? Is the lock part jammed, or just the spring latch?

When opened, does it pull towards you or push away?

Thank you so much, PigletJohn. A handyman has agreed to come and look at it in an hour, but if he can't sort it, I'll be back here with pictures...

It's the spring latch that's jammed.