Looks like there is some trouble happening in Oxford Circus. BBC reporting police
http://www.bbc.co.uk/news/live/uk-42117403
The Metropolitan Police said officers were called at 16:38 GMT to “a number of reports of shots fired” on Oxford Street and Oxford Circus Tube station.
“Police have responded as if the incident is terrorist related,” a statement said.
“Armed and unarmed officers are on scene and dealing along with colleagues from British Transport Police.
“If you are on Oxford Street go into a building and stay inside until further direction. Avoid travelling to the Oxford Street area.
“At this stage police have not located any casualties.”