Can anyone please advise best course of action when a mortice lock fails in
the locked position ?
Have a 5 lever ERA mortice lock on front door in addition to standard Yale
rimlock.
Locked the front door behind me this morning and it seemed a bit stiff and
tonight it will not reopen. However hard I turn the key the bolt will not
return and so door is effectively permanently locked. Have gained access to
house and tried all spare keys including almost brand new spare ones with no
success.

Any tips on how to retract the bolt ?

As we have another lockable exit door I have the luxury of not having to
panic and cut lock out of door or frame.
Yellow pages is full of Locksmiths with 24 hrs callout. Can any of
these----local or national---be recommended ?
Will my buildings insurance help me if I have to employ someone to reopen
the door ?
All advice gratefully received.

John Chapman