On 28/06/2007 17:09, John wrote:

I heard of someone who had locked themselves out (after leaving by another
door with a latch bolt) and called a locksmith (another key was in the lock
on the inside). He filed a bit off the end of the key and it allowed the key
to then open the lock.

Any views on why this worked?

It was then short enough to NOT touch the key in the inside cylinder?