A chief constable has expressed deep concern that a patient with serious mental health problems had to sleep in the back of a police car in a hospital car park because there was no bed available for her.

Katie Simpkins, 23, from Corsham in Wiltshire, was detained under the Mental Health Act for her own safety but there was no hospital bed available in the whole of the county. Officers allowed Simpkins to sleep under a blanket in the back of their patrol car and watched over her until a bed became available.

She and her husband, Tristan Simpkins, 25, released a photograph of her in the back of the police car to try to raise awareness of the lack of beds available in such situations.

The chief constable of Wiltshire police, Mike Veale, said officers were often having to take responsibility for vulnerable people with mental health problems who ought to be in the care of health professionals.

He said that in the past week officers had persuaded a 17-year-old girl with schizophrenia to come down from the roof of a car park, only to be told there were no beds available for her anywhere in the county. He also said officers held a man in a cell for more than 48 hours because there was no mental health care facility available for him.

Veale said: “A police officer is not the appropriate person to be dealing with a vulnerable member of the public who has an illness and poses a real risk to their own health and wellbeing. My police officers and staff face difficult, stressful and sometimes dangerous situations every day. They are not trained to provide specialist care to people with complex problems. They don’t know the background of these people, their medical history or their personal details.

“These issues have always been here for the police, and not just in Wiltshire, but are becoming more acute as austerity bites and there is increased pressure on social care and healthcare services.”

Police had detained Simpkins under section 136 of the act early last Saturday when she suffered a mental health crisis. Her husband said police rang round but could not find a place for her in a mental health unit.

They took her into the custody suite at Melksham police station until later on Saturday afternoon, when officers were told a bed was available at Green Lane hospital in Devizes. However, when they got there at 5pm they were told it was not ready.

Tristan and Katie Simpkins. Photograph: Tristan Simpkins/PA

Mr Simpkins said: “The hospital suggested she go back to custody and they would call when it was ready, but the police officer said custody is not the right place for her. He didn’t want to risk her missing the bed so he said they’d wait, and he’d wait with us.

“Katie had her medication, became drowsy and he let her sleep in the back of the police car with her blanket. When I saw her lying in the back of the police car I felt frustrated, but I’ve become used to it. I feel hopeless.”

He praised the way the police had tried to help. “It wasn’t their fault they couldn’t get a bed but these officers were all really lovely with her,” he said. She was finally admitted at 9pm.

Angus Macpherson, the police and crime commissioner for Wiltshire and Swindon, said: “This is not an isolated incident. Such incidents are happening once or twice a month [in Wiltshire]. The picture of Katie Simpkins huddled beneath a blanket in the back of a Wiltshire police car has understandably caused concern to the public. I have said it before and I will say it again: custody is simply not the right place for someone in a mental health crisis.”

Avon and Wiltshire Mental Health Partnership NHS trust confirmed there were only two beds available for people detained under section 136, which gives police the power to take a person from a public space to a place of safety.

A trust spokesperson said: “We work closely with the police to ensure they know the availability of places of safety. In this instance we were unable to provide a bed straight away and there clearly could have been better communication. We apologise and will be mindful of this in the future. Once the matter came to our attention, we made contact with Mr Simpkins to give him and his wife our full support.”

Last month the government announced that the Avon and Wiltshire trust was among those that had successfully bid for a share of a £15m fund to improve provision of mental health places of safety.

A Department of Health spokesperson said: “When a person is experiencing a mental health crisis they need the right care, in the right place and at the right time. We are fully committed to improving mental health services across the country.”