The driver of a car that ploughed into football fans during Liverpool’s Premier League victory parade is being held on suspicion of attempted murder, police have said.

Merseyside Police said a Ford Galaxy avoided a roadblock by tailgating an ambulance responding to reports of a member of the public having suffered a heart attack.

The force said the 53-year-old man, from the West Derby area of the city, was also being detained on suspicion of dangerous driving and driving while unfit through drugs.

A total of 50 people, including children, were treated in hospital following the incident in Water Street, which happened shortly after 18:00 BST on Bank Holiday Monday.

Det Ch Supt Karen Jaundrill said there were 65 confirmed casualties following the incident.

Of the injured, police said 11 people remained in hospital.

All are said to be in a “stable” condition.

Merseyside’s Assistant Chief Constable Jenny Sims said: “It is believed the driver of the Ford Galaxy car involved in this incident was able to follow an ambulance on to Water Street, after the roadblock was temporarily lifted so that the ambulance crew could attend to a member of the public who was having a suspected heart attack.”

She added: “There was no intelligence to suggest an incident of this nature would take place and, as we previously stated, the incident is not being treated as terrorism.”

The senior officer defended the policing operation during the parade, which attracted hundreds of thousands of people to the city.

She told reporters that the force had planned for “all contingencies”, including road closures and an armed police presence.

Assistant Chief Constable Sims said “an extensive investigation into the precise circumstances of the incident” was continuing, and once again urged people not to speculate about what had happened.

The force has asked anyone with information about the incident to refrain from sharing it online and instead pass it on to police.

Earlier, Liverpool City Region mayor Steve Rotheram suggested the suspect’s car should not have been on Water Street and said questions about how it was able to be driven there were “legitimate”.

Water Street remains closed while investigations continue into the incident.

A police cordon remains in place, while members of the public have begun to lay flowers, cards and toys near the crash scene.

Huge numbers of joyful Liverpool fans packed the city centre on Monday and lined the 10-mile (16km) parade route as the Reds celebrated winning their second Premier League crown and 20th top-flight league title.

Witnesses graphically described the terror of what happened after the Ford Galaxy smashed into a tightly packed section of the crowd that had gathered on the pavement outside a bar.

Some feared it was a terrorist attack.

Robbie Potter, who was severely injured in the 2017 Manchester Arena bombing, was on Water Street.

“I thought it was happening again,” he told the BBC. “How did a car get through?

“From the videos, they’ve been very lucky.”

Meanwhile, Daniel Eveson’s partner was dragged under the car’s wheels and his baby son’s pram was tossed down the street.

For a moment, he said he did not know if they had survived.

Mr Eveson, from Telford, told BBC Radio Shropshire he saw “people going flying and people screaming and just terror, pure terror”, adding: “I thought I’d lost everything.”

The car struck Mr Eveson in the chest before his partner went under the wheels and was dragged down the road.

The impact spun their son’s pram about 15ft (4.5m) down the street.

Mr Eveson was able to locate his son, who was unharmed, and leave him in a restaurant with helpers as he went back to search for his partner.

Jack Trotter and his girlfriend Abbie Gallagher, from Newtownards in County Down, were hit by the car after it surged towards them.

“The first thought that I got was: ‘Where’s Abbie? I need to find Abbie’,” the Liverpool fan from Northern Ireland told the BBC.

“Where’s Abbie? You know she could be anywhere at this rate and lucky enough she was screaming my name and I found her.”

Mr Trotter was taken to hospital by ambulance and kept in overnight.

He sustained injuries to his back and leg and is now walking with crutches.

Following the incident, messages of support have been sent to the people of Liverpool, including from the King, who said: “I know that the strength of community spirit for which your city is renowned will be a comfort and support to those in need.”

The Prince and Princess of Wales also said they were “deeply saddened” by the incident, adding: “What should have been a joyful celebration ended with tragedy.”

The Princess Royal visited the Royal Liverpool University Hospital, where medical staff spoke of how they were “very, very fortunate” that more people had not been injured.

Reds legend and former captain Steven Gerrard posted on Instagram that he was “shocked, sickened and saddened” over the incident.

Meanwhile former Liverpool FC manager Jurgen Klopp wrote that his “thoughts and prayers are with all those who are injured and affected”.

“You’ll never walk alone,” the statement concluded, referencing the club’s famous terrace anthem.