An outraged man found an elderly woman with dementia wandering in the street after a door was accidentally left unlocked at her care home.

Electrician Jason Langstaff, 44, said he spotted a confused woman, with a blanket wrapped round her shoulders, walking down Woodland Way, off The Warren, in Kingswood, at about 4.15pm on Friday.

She had walked out of the nearby Warrengate Nursing Home, in The Warren, which houses elderly residents who have dementia and diseases such as Alzheimer’s, and is located close to the busy main road Brighton Road.

The care home admitted the mistake to the Epsom Guardian and said it had changed its policy around the checking of how doors are closed following the incident.

Mr Langstaff said he tried to help the woman, who he said was not distressed, but confused and anxious. He said he did not know where she had come from, and stayed with her to make sure she was safe.

He said: "I was walking with her, trying to talk to her and establish where she was from. She wouldn’t let go of my hand."

Mr Langstaff, who said his 94-year-old grandmother is in a similar situation to the elderly woman, had been working at a house in Woodland Way.

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Warrengate Nursing Home in The Warren

He said he stayed with the woman, while the son of the client Mr Langstaff was working for drove to the Warrengate Nursing Home to inform it of what had happened.

The electrician added: "It’s quite raw and close to home when you have someone in a similar situation that relies on the care of other people. You really trust in people."

Mr Langstaff said a carer from the home was sent to collect the woman and he accompanied them both back to Warrengate, which he said was about a quarter of a mile from where he came across the woman by chance.

At the home, he confronted Mabs Rajan, 66, owner of Claremont Care Services, which runs the nursing home.

While Mr Langstaff said he was concerned about the woman's welfare and had raised his voice because he did not want the matter "brushed under the carpet", Mr Rajan said the electrician was trespassing and being aggressive.

Both parties ending up calling the police, with officers attending and giving the men “words of advice”.

Mr Langstaff said: "It’s just so negligent. It’s worrying that somebody can wander out into any kind of danger and not be missed.

"I was disturbed that she could have been gone all that time, possibly killed, and no-one would have known.

"If she had come out of the care home and turned left within 30 feet she would have been under a car, she would have been killed."

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Mr Rajan said the resident left the home at about 4.15pm and a staff member realised she was missing at 4.40pm, before dinner.

He said one of the home's code-locked doors had not been shut properly on Friday, allowing the elderly woman to wander off, but he did not know exactly who left it unlocked.

Mr Rajan said: "This was not negligence. This was an unfortunate incident. There was something to learn. We have a hundred visitors and professionals coming in and out every day.

"Now having learned from it, the policy is doors must be closed by a member of staff, not relatives." Mr Rajan said the home reported the episode to social services, did a risk assessment on the resident, informed her relative and told staff that they must be the ones to shut doors from now on.

Mr Rajan said the woman walking out of the care home was an "unusual event". He added: "There was no injury, no accident. She probably enjoyed the little walk out of the premises."

In May 2011, the CQC found the home was failing in 12 key areas including care and welfare, nutrition, management of medicines and suitability of equipment.

In July last year, it was found to be meeting all standards except care and welfare and records - areas which it subsequently met in a follow-up inspection in January this year.

In June, a nurse at the home, Daniela-Florina Mysllinj, was struck off for a year after a string of incidents related to her time at Warrengate, including her shouting "are you mad?" at a dementia patient.