Mentally-ill teenagers will no longer be held in police cells under expected reforms

Overhaul will also see police cells used only as a place of safety for adults

Theresa May is reported to be revealing changes to mental health laws in England and Wales (PA)

Teenagers with mental health problems will no longer be detained in police cells will no longer be held in police cells, under an overhaul of reforms expected to be announced this week.

Theresa May is reported to be revealing changes to mental health laws in England and Wales.

The overhaul will also see police cells used only as a place of safety for adults, who are held their when their behaviour is so extreme they cannot be managed elsewhere.

The joint Home Office and Department of Health review of sections 135 and 136 of the Mental Health Act will also reportedly recommend reducing the maximum length of detention of someone in mental distress from 72 to 24 hours.

The move by the Home Secretary comes after reports that Devon and Cornwall Police force complained it was forced to hold a 16-year-old girl with mental health problems in a cell for two days because there was no hospital bed available. The girl was eventually placed in an adult hospital bed.

The number of times police cells have been used to hold mentally ill people has fallen in the past four years from 8,667 occasions in 2011-12 to 6,028 in 2013-14.

However, police cells are still used instead of hospital beds or community places in more than a third of cases, particularly for children under the age of 18, according to The Guardian. The paper states 236 children sectioned in 2013 were placed in a police cell for a "non-criminal health" issue.

Charities and care providers have warned beds must be available in order for the reforms to be carried out successfully.

Sarah Brennan, chief executive of charity YoungMinds, said: "It is appalling that children and young people are held in police cells because there is no other place of safety for them.

"However, this legislation alone is not the answer. There must be funds available so that there is an increase in the number of safe appropriate beds that local areas can access easily and quickly.

Additional reporting by PA