The Sentinel (Stoke) -- A high-tech monitoring system has been introduced in police cells in Staffordshire to prevent prisoners taking their own lives.The "Life Signs" system is currently being pioneered by the force at Stafford police station and if it proves successful it will be extended to every other custody suite in the county.Assistant Chief Constable David Swift said: "We need to make sure the system works properly before we roll it out to the rest of Staffordshire. "If it proves as effective as we hope, it will be extended. Early signs are encouraging and this could be a great step forward."This is part of an ongoing initiative to minimise the risks to people in our custody."Equipment constantly monitors movements in a vulnerable prisoner's cell and also checks whether they are breathing regularly.An alarm sounds in the custody suite if the ultra-sensitive machines think anything is wrong.Police say all prisoners who have been categorised as being a potential danger to themselves would eventually be placed in cells monitored by the "Life Signs" equipment.They say it would act as back-up to the 10-minute cell visits already carried out and closed-circuit TV cameras.Chief Constable John Giffard said: "We have, following the risk assessment of custody areas, carried out extensive works within cell blocks to ensure that minimal risks to detainees and staff are present."It is pleasing to note that the number of incidents of self-harm has been significantly reduced."While we are happy with these developments, we do not feel complacent about the possibility of self-harm."Staffordshire was praised earlier this year by the Police Complaints Authority for a string of measures it had already put in place to cut deaths in custody.The force has had no deaths in its cells for two years, the last being 25-year-old Kirk Murphy, from Abbey Hulton, who hanged himself with his own shoelaces in a cell at Hanley police station after spending two days without drugs.His former wife Paula, who has now devoted her life to campaigning against the evil of drugs by touring schools and youth groups, was critical at the time of his death of why tighter restrictions and visits were not in place.Among the measures the PCA praised Staffordshire Police for taking were the use of closed -circuit TV in the cells of vulnerable prisoners, improved training for staff, making drugs and alcohol counsellors available and questioning detainees when they are booked in about any history of self-harm or mental illness.