A nine-year-old girl has become the third child to die after the Southport stabbings, Merseyside Police said. A 17-year-old boy, who cannot be named for legal reasons, remains in custody accused of murder and attempted murder following the incident in Hart Street, Southport, on Monday.

A police statement said: “Sadly we can confirm that a third child has passed away as a result of injuries sustained in a knife attack in Southport yesterday morning, Monday July 29. The nine-year-old girl died in hospital in the early hours of this morning, Tuesday, 30 July. We can confirm that the children who died yesterday were girls aged six and seven years.

“Eight other children suffered stab wounds sustained during the attack, and five of them are in a critical condition. Two adults are also in a critical condition after being injured during the incident.

“Our specialist family liaison officers are providing support to the families at this terrible time. Yesterday, officers arrested a 17-year-old male from Banks and he remains in police custody.”

A fully-booked club for children, which was advertised as a dance and yoga workshop as well as bracelet-making, quickly became something “like a horror movie”, witnesses to the deadly stabbings have said. Nine children were injured in the stabbings, alongside the three who died and two adults who remain in a critical condition after attempting to protect the youngsters.

Tributes have been paid on social media to the bravery of dance and yoga teacher Leanne Lucas after she was attacked in the incident. Ms Lucas was named as an organiser of the event run by Southport-based business Enlighten in a post on Facebook.

Yvette Cooper said “it’s important that police pursue every single avenue” after three children died in a mass stabbing in Southport. Merseyside Police previously said the attack on Hart Street, which also left five other children and two adults in a critical condition, was not being treated as terror-related.

Asked why, the Home Secretary said: “There is a serious criminal investigation underway because this was a horrific attack. It’s important that police pursue every single avenue and that is what Merseyside police are now doing.

“I support Merseyside police in that work, but it’s immensely important that they need to be able to continue that and they will provide updates. You’ll understand that I’m not going to say anything that would cut across their investigation or prejudice that investigation as I take that investigation immensely seriously into this truly horrific attack.”