Front door lock not locking correctly, or is it something else?

[jameslpool]

Hi, this morning our front door lock has started not locking, below are the pics of it. the highlighted part in yellow seems stuck in.

I don't know if my daughter has found a way of setting it so that it stays in, or if it's broke somehow?
I have never known a way to keep that part in so that the door just stays lope?

When i life the handle, it does partially lift the bits that go into the frame, but not enough.
From the inside if i turn the lock, it only partially lock and feels really loose.
From the outside if i lock with my key, the door seems to just open.

Has anyone please got any thoughts if my daughter has managed to just keep it open somehow? or if i just need to get a locksmith asap?

Thanks
James

 

[crank39]

The plastic bit that says ERA on it slides up and keeps the latch in but yours looks down from the picture