An investigation is being carried out following the stabbing of an 11-year-old girl in Leicester Square.
Police were called at 11:34hrs on Monday, 12 August and officers were on scene within four minutes.
They gave emergency first aid until the arrival of paramedics from the London Ambulance Service.
A girl, aged 11, was taken to hospital with stabbing injuries. She is seriously injured and will require further treatment, but her condition is thankfully not life threatening.
Her mother, aged 34, also suffered minor injuries.
A 32-year-old man was arrested at the scene. Officers are not looking for anyone else in connection with the attack.
Detective Chief Superintendent Christina Jessah, in charge of policing for Westminster, said: “This is a horrific incident and our thoughts are with the victims and their family. We will continue to provide support to them over the coming days and weeks.
“I would like to pay tribute to the members of the public, including staff from local businesses, who bravely intervened in this incident. They put themselves at risk and showed the best of London in doing so.
“An urgent investigation is now ongoing and detectives are working to establish the details around exactly what happened.
“At this stage we don’t believe the suspect and the victims were known to each other.
“While we continue to work to establish the suspect’s motive, at this stage there is nothing to indicate the attack was terror-related.
“Detectives will be keen to speak to anyone who was in the area and may have information that can assist with their enquiries. I would urge anyone who can help to get in touch.”
Witnesses, or anyone with footage or photos of the incident, are asked to call 101 or to contact Crimestoppers, anonymously, on 0800 555 111, giving the reference 2745/12AUG.