Prisoners will get cosy cells after police chiefs agreed to invest more than £400,000 in better heating.

Senior officers acted after detainees, solicitors, visitors and police staff complained that custody suites were too cold in winter and too hot in summer. They feared poor conditions could lead to bad behaviour by inmates, and interview evidence could be excluded from court if codes of practice were breached.

The problem was so bad that sensitive CCTV electronic equipment was being affected by the extremes of temperature.

The force has now announced that cells at three North Yorkshire Police stations, York, Harrogate and Northallerton, will get a major heating and ventilation renovation programme.

The three custody suites, which contain 44 cells, operate 24-hours-a-day, all year round, and process an average of 18,600 prisoners each year. The new facilities will also affect medical and consultation rooms, as well as the central booking-in areas for new arrivals.

Work is expected to start on site in August, and the rolling programme of upgrades will take 16 weeks to complete.

Members of North Yorkshire Police Authority, who oversee how the force is run, are expected to set aside £401,500 for the work when they meet ont Monday.

In a report, Chief Inspector Glenn Gudeon, who is responsible for the administration of justice, said some of the heating and ventilation systems were up to 15 years old.

He said: "Independent custody visitors, detainees, their legal representatives and the staff working in custody suites have all found them to be too hot in summer and too cold in winter, with constant poor ventilation and inconsistent heating between cells.

"Engineering consultants found the current systems were in a poor state and unable to provide consistent air temperatures or proper ventilation. This is not only affecting staff and customers, but also temperature sensitive electronic equipment such as CCTV."

He said: "The Police and Criminal Evidence Act (PACE) codes of practice govern the detention, questioning and treatment of detainees.

"The codes of practice state that cells must be adequately heated and ventilated. Extremes of temperature could be classed as oppressive and have a potential impact on detainee behaviour.

"The cost of potential claims for breaches of codes of practice are not just monetary, there is potential for evidence being excluded at court."

Updated: 09:48 Friday, April 15, 2005