Nothing to do with security
I think you all must remember that the UK's security regulations are primarily intended to protect govenment ministers and civil servants from critsisum in the press.
A whole raft of the regulations are utterly useless from a security point of view and some are counterproductive but even if the minister in charge can see this he won't do a thing about it because some one with a financial interest in the yogurt police will leak a story to the press that he is being weak on security.