The BBC is reporting three Tube stations evacuated after 'incidents' and one bus has also experienced an 'incident', whatever that means.
Edit: Police say they're not treating it as a major incident at the moment, and the Tube hasn't been entirely shut down either. Only one report of an injury, at Warren Street. There actually seems to be a strong element of farce about it – farty little explosions that don't even destroy the rucksacks they came from, an orderly evacuation from one Tube train until just one person was left on it, who then ran like the clappers out of the station pursued by shouts of 'oi, you!'. Too early to be complacent of course, but so far so facile.