Hounslow West station was closed this morning as police investigate a stabbing.
Metropolitan Police confirmed that a serious assault had taken place outside the station in the early hours of this morning.
A police spokeswoman told City A.M: "Police were called by the London Ambulance Service at 3:40am on Tuesday, 29 September, to a report of a seriously injured man in Bath Road, Hounslow near to Hounslow West underground station.
"The man - believed to be aged in his 30s - had been assaulted. He was taken to a central London hospital suffering a head injury. He is in a critical condition. Officers from Hounslow CID are investigating."
Three people have already been arrested in connection with the incident, "some of whom had themselves sustained injuries", the spokeswoman added.
Bath Road is closed to the west of Hounslow, as is Hounslow West underground station.
South West Trains said the west London station was “likely to remain closed for several hours” and advised commuters to use alternative stations such as Hounslow Central or Hatton Cross instead.
Reminder - A3006 Bath Road (Hounslow) is closed both ways between Vicarage Farm Rd & Martindale Rd (overnight incident). Use other routes.— TfL Traffic News (@TfLTrafficNews) September 29, 2015
Tickets are also being accepted on local buses, although some diversions are in place.