Strange Sights in Parliament

My great thanks to a favourite comment leaver and all round good egg who will remain anonymous for sending this wonderful picture (click to enlarge) which they took at lunchtime. This was outside Commons' Leader Jack Straw's Office and on his incoming mail tray. Suspicion is that it could be from a deputy leadership rival knowing Jack's passion for chocolate cake slipping a bit of his favourite gateux laced with a bit of arsenic. However, what is peculiar is why was all the incoming mail brought into the office except the chocolate cake? My suspected response from Mr. Straw's office who I decided not to contact as they probably have more important issues would be something on the lines of:

"The chocolate cake arrived at Jack's office completely covering itself wearing and cake case and covering its top with icing. Jack asked whether the cake would mind removing it's veil of chocolatey crystal icing as he felt he couldn't communicate with the cake properly. The cake didn't respond and kept covered. Jack then asked the cake to wait outside and to have a serious think about uncovering itself. The cake is still there thinking."