Slang meaning of GONE FOR A BURTON

GONE FOR A BURTON means: Gone for a Burton is slang for missing, broken.Gone for a Burton was British RAF slang for dead, shot−down.

What is the slang meaning/definition of GONE FOR A BURTON ?

GONE FOR A BURTON means: Gone for a Burton is slang for missing, broken.Gone for a Burton was British RAF slang for dead, shot−down.