A man with heart problems suffered an angina attack while in the cells at Dewsbury Police Station.
Paramedics were called to treat Tim Allen when he fell ill on Tuesday afternoon.
Mr Allen said he had the attack after he was kept in the cells for hours without access to his medication.
He now plans to lodge a formal complaint about his treatment.
“They were bombastic and demeaning to me,” he said. “I’m 51 years old. I’ve got no record. I can’t understand how they treated me like some criminal.
“I didn’t get a blanket or anything to eat or drink. They treated me like I’m there every week.
“Seven hours they had me in there. I still feel poorly now.”
Mr Allen, of Ashworth Close, Dewsbury, said he told officers that he was due to take medication for a heart condition when he voluntarily attended the station at around 12.20pm.
He was arrested on suspicion of using threatening, abusive or insulting words or behaviour to cause harassment, alarm or distress, and taken into the cells.
“I told them I’m due my tablets at 2pm and 4pm, and asked if I would be home,” Mr Allen said. “They said folk usually say that and they can miss them. I said I did need them for my heart.”
But police said yesterday that Mr Allen had not told officers about his heart condition.
Supt Julie Sykes said: “The welfare of anyone taken into police custody is of paramount importance. To ensure appropriate care can be provided it important they inform us of any pre-existing conditions when they are asked.
“In this case the individual was lawfully arrested and when asked about existing medical issues he did not disclose he had a heart condition to officers.
“When it became apparent that he was unwell he was given medication and confirmed he had not informed officers about his heart condition when asked.”
She said paramedics were called, but Mr Allen refused hospital treatment and the offer of a lift home.
A formal complaint had not been received by police when the Reporter went to press.