Irene Sharples, 92, was living at Alexian Brothers Care Centre on St Mary’s Road in Moston when the door fell on her during. She died just under four weeks later as a result of her injuries.

The Healthcare Management Trust and construction firm Rothwell Robinson Ltd were both prosecuted by the HSE after an investigation found dementia-sufferer Sharples had been able to wander into a building site at the home.

Manchester Crown Court heard the Healthcare Management Trust, which runs the care home, had hired Rothwell Robinson to convert a ground floor bedroom and en-suite into two toilets and a store room.

The company began the work on 2 November 2010 and several tradesmen, including two joiners and a plumber, visited the site over the following days.

The court heard staff at the care home heard a loud thud and a cry for help. When they went to investigate, they found Sharples on the floor inside the former ground floor bedroom with a fire door on top of her.

It took three people to lift the door off her and she suffered a broken hip.

Sharples spent eight days in hospital but her condition deteriorated when she returned to the care home and she died on 2 December.

The HSE investigation found the healthcare firm and building company had both failed to make sure the room was locked at the end of each day and also when it was left unoccupied.

The fire door had been removed from the en-suite during the building work and leant against the wardrobes.

The court was told Mrs Sharples knew the resident who previously lived in the room and would occasionally walk into that room as she wandered around the care home.

The Healthcare Management Trust, of Queen Anne’s Gate in London, was fined £20,000 and ordered to pay £7,500 in prosecution costs after pleading guilty to safety breaches.

Rothwell Robinson Ltd, of Worsley, was fined £10,000 with costs of £7,500 after pleading guilty to the same offence.

Speaking after the hearing, HSE Inspector Laura Moran said: “Both firms clearly knew there were vulnerable residents living at the care home but they still allowed the door to what was essentially a building site to be left unlocked on numerous occasions.

“Sadly, Mrs Sharples was severely injured when she wandered into the room, presumably looking for her friend, and ultimately lost her life because of the failings of the Healthcare Management Trust and Rothwell Robinson.

“Following the incident, the companies introduced a new procedure which meant workers had to collect and return a key at the start and end of each day, and lock the door when there was no one inside.

“If this system had been in place from the start of the building project then Mrs Sharples would never have been able to get into the room.”