West Mercia police force has apologised and paid £10,000 compensation to a man who was wrongfully arrested for taking a photograph of a bank doorway and pushed face down into a puddle by officers as they marched him to a police station.

Under the highly unusual deal West Mercia's chief constable, David Shaw, will write a letter of apology to Anthony Finnegan. The force has admitted liability for the incident and will pay Finnegan £10,000 plus his legal costs and delete all records of his arrest. As yet, neither of the officers involved has been disciplined.

Finnegan, a 45-year-old construction worker, is a keen amateur photographer. On the day in question in July 2009 he was taking pictures in the centre of Shrewsbury, one of which was of the front lobby of a high street bank in a period building.

He was approached by a police constable and a community support officer (CSO) who, Finnegan said, asked why he was taking "discreet photographs" of a bank. "I said: 'There's nothing discreet about this, it's an SLR camera. If I was being discreet I'd use a phone'," Finnegan explained.

The police officer, PC Ben Hocking, pushed Finnegan's shoulder before searching his pockets. Finnegan said he was completely cooperative and suggested they go to the police station, partly as he was not carrying identification but also because he was embarrassed to be searched publicly in his home town.

Finnegan said he was still relatively unworried until, while they walked to the station, he told the officers he planned to roll and smoke a cigarette. As he rolled it, Hocking repeatedly shoved his arm, spilling the tobacco.

"Now I was shocked," Finnegan said. "By this stage people were looking at me. I was walking down the street with two officers, one of them's got hold of my camera bag and the other keeps on shoving me."

As they drew near the town centre police station, Hocking pulled Finnegan's thumb back sharply to restrain him, before the two officers pushed him to the ground.

Finnegan explained what happened: "He grabbed me in a thumb lock and I pulled away from him, going: 'What are you doing?' I got taken to the ground, face down into a puddle, and the CSO, who's about 18 stone, his knee went into my ribs, which cracked or broke the back of my ribs."

A subsequent doctor's examination found other injuries, including abrasions and bruising.

Finnegan was placed in painfully tight handcuffs and driven to another police station, where he was told he had been arrested for a public order offence and placed in a cell. He was released at about 9pm, seven hours after he was stopped. It took police two months to confirm he would face no further action.

The case was taken up by Bhatt Murphy, a London-based firm of solicitors specialising in civil rights cases. Fiona Murphy, who represented Finnegan, said: "We welcome the chief constable's decision to admit liability, to apologise and to destroy the records of Mr Finnegan's detention. We hope that this complete resolution of the claim will enable the force to learn lessons from this regrettable abuse of police powers."

Finnegan said that while he is glad to have cleared his name he remains dismayed that West Mercia police took no disciplinary action against the officers involved.

"I still see them in town. That's what pisses me off most. It's intimidating. If I see one of them I'll take a different route. Every time I go into town I scan the street for a high-vis jacket."

A spokesman for West Mercia police said that as some details were still being worked out "it would therefore be inappropriate to comment further at this time".

• This article was amended on 8 June 2012. The original gave Anthony Finnegan's age as 49. He is 45. This has been corrected.