MI5 probably has access to the embassy's CCTV feed and has been monitoring him ;) I prefer the version where Anonymous sends 1000 Julian Assange lookalikes to

MI5 probably has access to the embassy's CCTV feed and has been monitoring him ;) I prefer the version where Anonymous sends 1000 Julian Assange lookalikes to flood the embassy's entrance and that allows for Julian to escape through the sewer