The Independent Police Complaints Commission (IPCC) has rapped Lancashire Police over how the force dealt with a man with a head injury in custody.
The 22-year-old Preston man was taken into custody on November 1, 2014, after he was held in connection with a street disturbance in Ribbleton.
Every effort is made to safeguard the welfare of detainees in police custody, including a thorough risk assessment of each upon arrival
Police were told he had been unconscious but was on his feet when they arrived and paramedics concluded he had no injuries.
The man did not disclose he had been knocked out or injured but after a nurse examined him in custody at around 5pm the following day, he was taken to hospital and found to have a bleed on the brain.
He underwent surgery and was later discharged.
An IPCC probe found a lack of understanding of the importance of rousing checks and deficiencies in the way they were conducted, along with other shortcomings, and it made several recommendations for improvements.
A Lancashire Police spokesman said: “Every effort is made to safeguard the welfare of detainees in police custody, including a thorough risk assessment of each upon arrival. However we must learn the lessons from incidents like these.
“Issues identified by the IPCC, including better record keeping and increased use of telephone medical advice, have been addressed.
“It has been concluded there was no individual misconduct.”