Terror Alert.

At around 18:00 MI5 issued a terror alert to police at all major transportation hubs (airports/seaports/railway network).

Earlier in the day the American State/civil service opened a dialogue with Britain over how much British Petroleum would like to pay for the Deep Water Horizon rig explosion and the Gulf of Mexico oil spill that followed. Obviously this discussion involved reference to Britain's own off-shore drilling operations in the North Sea. Norway also has a stake in North Sea oil so they joined the discussion by arresting one of their Iraqi Kurd pets for apparently trying to hijack a passenger jet.

So Britain's terror alert was the British state looking at Norway and going "WTF going on?"