Liverpool parade crash: what we know

Four people were in a serious condition in hospital on Tuesday after a car ploughed into a crowd of football fans celebrating Liverpool's Premier League title victory.

Here is what we know:

What happened?

Just before 6:00 pm (1700 GMT) on Monday, as the parade wound up, a car rammed into the crowd on Water Street in central Liverpool, which had been shut to traffic.

The car, blocked by angry bystanders, reversed then accelerated, knocking over people on both sides of the road, according to videos posted on social media.

Several people were knocked over or thrown onto the bonnet. Four were trapped under the car, including one child who was seriously injured.

How many people were injured?

The emergency services said 47 people were injured, including four children.

Twenty-seven people were taken to hospital, where four were in a serious condition, said Liverpool region mayor Steve Rotheram.

Twenty others were treated at the scene on Monday evening and were able to return home.

What about the driver?

Merseyside Police quickly announced that "a 53-year-old white British man from the Liverpool area was arrested", in an unprecedented move to quell social media speculation.

British police do not normally release the ethnic identities of suspects.

But the force had to deal last year with the aftermath of a mass stabbing in nearby Southport, in which three young girls were killed at a Taylor Swift-themed dance party.

Online rumours spread by far-right figures about the identity of the attacker was blamed for widespread riots targeting asylum seekers.

Why did it happen?

Merseyside Police Assistant Chief Constable Jenny Sims ruled out "terrorism" as a motive.

"We believe this to be an isolated incident and we are not currently looking for anyone else in relation to it," she told a news conference on Monday evening.

What don't we know?

In line with procedure, police have not released the identity of the man arrested nor given an indication about why the incident happened.

Questions are being asked about how the driver came to be in a road that was closed to traffic and whether he panicked when surrounded by an angry crowd.

Harry Rashid, a witness who attended the parade, told the BBC the driver looked "emotional" and "agitated".

"His hands were moving about. He was trying to close the door of the car, I think, because they've tried to pull the door open and then he was trying to close it," he added.