Darren Gardner, an officer at HMP Hewell prison, tried to make a 'code blue' call for help to HMP Hewell's communications centre after discovering Paul Coley, aged 44, from Wolverhampton, but his radio would not work so he had to make the call by phone from his office ten metres away. Officers now keep a spare battery with them in case of a repeat of a similar incident.
The inquest at Worcestershire Coroner's Court in Stourport also heard he had not made an hourly note on an audit of his visits to Mr Coley's cell, as he was being kept under observation.
Mr Gardner said he had conducted the hourly checks, but had not put a note on his file until some 30 minutes after he should have because he had other business to attend to.
Coley, of Vicarage Road, All Saints, had been kept under observation by Mr Gardner the previous night and those observations were to continue when he came on duty on New Year's Eve, 2013 at 8.45pm.
However, when he went to check on the prisoner by looking through a hatch in the door, the cell was in complete darkness with no lights or television on so he switched on a night light outside the cell door to see if he could see in and at this point noticed Mr Coley stood up at the back and leaning against a cupboard.
"He looked like he was standing watching the TV or waiting for the kettle to boil. I noticed there was a ligature attached to his neck," Mr Gardner said.
After making the code blue, Mr Gardner was joined by night orderly officer James Wall and the pair began attempts to resuscitate Mr Coley after Mr Gardner had cut him down.
However, Mr Wall, who also spoke at the hearing, said there were no signs of life from Mr Coley as his chest was not rising when mouth-to-mouth was given.
The inquest has previously heard how the prisoner, who was on remand, had discussed having suicidal thoughts with Dr Neeta Bhadauria, of Burntwood Medical Centre, but these were not noted in medical reports.
However, the GP said he had expressed similar thoughts in the past and had not followed them through, adding she believed his mood may have been low due to pain he was suffering from a deformed foot.
Mr Coley had been remanded in custody at the Worcestershire prison after being accused of pulling out a fake handgun during a theft at a Tesco Express in Upper Gornal.
The inquest continues.