A customer in Ashford got in touch after being locked out of the property. They still had the front-door key, but the high-security lock simply refused to open.
From the description, my first thoughts were either a dropped snib or a failed rim-lock backbox, but once I arrived it turned out to be neither of those straightforward possibilities.
The usual non-destructive opening attempts were not getting anywhere, so I asked whether there were any other possible entry points. There was a side-door mortice lock with a key left on the inside. That gave me another route into the property and avoided damaging the front-door security hardware.
Once inside, I removed the backbox from the front-door lock and found the real cause: a small internal pin had failed.
The external part of the high-security lock was still serviceable, so there was no reason to replace the complete system. I ordered the correct replacement backbox and returned the following day at a convenient time to fit it.
One useful reminder from this job: leaving a key inside a mortice lock can create its own security and access problems, so it is better not to make a habit of it.
