The actor walked into a police station in St Helens at 5.30am where he continues to be held for questioning.

Whittle, 29, is a favourite to win the BBC's Strictly competition but the broadcaster has made no comment about whether he will appear on tomorrow's show.

He had taken a break from training and returned to Liverpool, where Hollyoaks is filmed, to attend a party at the city centre's Parr Street Studios with colleagues from the Channel Four drama.

It is understood that after the party was over he left the venue and headed for his car at around 1.30am. It is alleged that as Whittle drove off, his vehicle struck the photographer and left him with minor injuries.

He was released after questioning on Friday afternoon.

Paramedics were called to the scene, on Duke Street, but the photographer, thought to be Steve Farrel, declined immediate treatment.

He later took himself to a hospital where he was treated for minor injuries before being discharged.

A woman who was answering Farrel's mobile phone today said he was not making any comment about the matter.

Police said Whittle presented himself at a police station four hours after the alleged incident.

A spokesman said: "Merseyside Police can confirm that a 29-year-old man from the Billinge area of Greater Manchester has been arrested on suspicion of assault.

"He remains in police custody where he will be questioned.

"This follows an incident in Duke Street, Liverpool city centre, in the early hours of this morning."

A spokesman for Parr Street Studios confirmed one of the venue's bars, Studio Two, was hired for last night's event by the Hollyoaks crew.

He said the alleged incident took place after the bar was closed for the night and some distance away.

A spokeswoman for Lime Pictures, which makes Hollyoaks, said it was a legal matter and it had no comment to make.