PM on Grenfell: I do not know why official help took so long to come

May speaks to firefighters as she visits Grenfell Tower.The prime minister has admitted she still does not know why it took so long for the authorities to help the victims of the Grenfell Tower fire.Survivors have repeatedly complained about the lack of a co-ordinated official response in the hours and days after, saying it left them feeling abandoned while food and clothing for victims was delivered by volunteers on an ad hoc basis.