Universal Lever Lock Pick

Most of my lock picking has been geared towards cylinder pin locks. The same skills can also be applied to wafer locks. There are, of course, many other types of lock mechanism. Warded locks were discussed in a previous post.
A lock mechanism I often see on the television is that of lever lock or some other design that uses this form of key:

Sometimes this is because the program is set in the past, or set in an old location. Often the lock is for a jail cell in some “developing” nation. My beloved Bogotas are of very little use against such a lock! Naturally I am curious as to how such locks can be dealt with.
The other day I encountered Houdini’s book “Handcuff Secrets”. Despite the title, he covers many other topics and it is an interesting read. One particular item he shows (p.71) is the ingenious device shown below, constructed from two pieces of steel and some brass tube.