I read this in the Evening Standard Lite today, the following from TheSun.co.uk
Oops! Surely when the media start taking pictures & a Eurostar security guard starts chasing after you,you'd realise your error and walk back, or, er, go and buy a paper!FRENCH police today apologised after one of their armed officers entered a shop at London Waterloo station with a gun.
The officer was making a purchase at the WH Smith outlet when she was spotted with the pistol strapped to her waist.
The policewoman is understood to be part of a French immigration team at the south London station's Eurostar internation terminal.
The French officers are allowed to carry firearms, but only in certain areas.
A Home Office spokesman said today: "We understand that one of the French national police officers based at Waterloo International inadvertently went to buy a newspaper at the station while still wearing a firearm.
"This is in contravention of the agreement we have with the French. We understand that the officer has since returned to France and the matter is being dealt with by the French police authorities at a senior level.
"The French have apologised for the incident. In an agreement with the
French, weapons may be carried. Since July 2001 a small number of officers from the French national police have been deployed at Waterloo International."
It is understood the officer had been helping a family who had reported their daughter missing. She had spotted the daughter at WH Smith and had walked into the domestic part of the station to get her and reunite her with her parents.