Border force have coughed and admitted it was them. The tweet of denial from the Met was probably not well thought out, border force, police etc all very similar to Jo public and the media.
UK confirms Russian plane was searched at Heathrow yesterday. Security Minister Ben Wallace: "It is routine for Border Force to search aircraft to protect the UK from organised crime & from those who attempt to bring harmful substances like drugs or firearms into the country."
Why the need to search the aircraft, should they not be searching off loaded pax, bags and cargo? Unless of course something was going to be off loaded at the last minuite