Note:  Do not rely on this information. It is very old.

Conscience Money

Conscience Money, an expression coined to represent sums sent anonymously to the Chancellor of the Exchequer by those who have unwittingly or wilfully defrauded Government of some of its dues. The name comes from the supposition that the sender of the money is impelled to this course by the stings of conscience. These stings, however, are seldom so keen as to lead him to reveal his name.