Dear RogerDear Uncle Arnie,
There is a colleague at work who keeps stealing my Jammie Dodgers from my desk when she thinks I'm not looking.
How can I politely ask her to stop doing it?
Exlax is now available in powdered form. Could you not sprinkle some on your Jammie Dodgers. If questioned you could say you found they seemed to have an odd taste, but seemed okay.
This last part will lead the thief into a false sense of security Espescially if you take one from the same packet in front of them.
Cheap and Cheerful