There were two British SOE [Brit counterpart to American OSS] Edged Weapons/Escape Aids in World War Two, a little of both.
The soles of your shoes would be replaced with custom soles. One had a zipper that ran down the center and you could place several [5 if I remember correctly] gold coins in them. Paying for safe passage, bribes, etc. The other sole had a flat dagger in it that when it was made and still hot, was shaped to fit along the bottom of the foot, the arch in profile...
The other was a sleeve knife that was almost identical except not shaped, just a flat, double edged dagger, and it was worn under the sleeve of a coat. It was fired by a Gambler's Jacob's Ladder type of mechanism. These were never issued as far as I know although the others were.
Another knife in this category that fit into the shoe...was heel blades. They were basically a tiny, non-pointed and slightly curved blade with a nail nick in some instances for opening, so if you were hogtied or otherwise restrained [remember, soldiers then and now hardly ever use handcuffs in combat, you would be tied in most cases] you could cut yourself free with these simple escape knives.
Also, there were coins made, if the Agent were being dropped into France, the coin would be French, etc., and on the other side of the coin was a blade similar to the heel blades. You have a 50/50 chance of avoiding detection if your coins had to be emptied out of your pockets during a search...