'Mum had severe dementia, so why did Northampton building society let someone take over her account?'

Nationwide said its staff are trained to check for dementia in its customers

The woman, who was also blind, had been noted by doctors to have "acute confusion" and diagnosed with deteriorating dementia when her stepdaughter was allowed to switch from being a co-signatory to becoming a joint account holder without staff at the Weston Favell branch of Nationwide raising concerns.

This change to the account allowed the £4,000 in it - from the elderly woman's pension and earmarked for care home fees - to be retained by the stepdaughter after her stepmother died in the summer of 2018, rather than being divided among all her children and stepchildren as part of her estate. There was nothing untoward in the switch, the stepdaughter did not benefit from the change and the money has remained untouched.

However, another of the woman's stepdaughters has complained to Nationwide that it should have done more thorough checks.

She said: "There is absolutely no way she had capacity at that time, certainly not when it was made a joint account.

"She had had dementia for months.

"My concern is that my mum was open to being abused financially and Nationwide have let it happen."

The stepdaughter whose name was added to the her stepmother's account said she had no intention of benefiting from the changes and said the money is untouched.

She said:"I didn't know that when mother died that would come to me."

She also said she had no idea her stepmother had dementia until she saw her death certificate.

She said: "We were never ever told that she had dementia.

"We probably thought maybe she was getting a bit forgetful

"She went into that care home because she was unsafe."

However, the daughter who raised the concern with the Chron showed this newspaper medical records from a month before the crucial account change saying she "does not have capacity" as a result of her dementia.

A spokeswoman for Nationwide said staff were trained to spot signs of incapacity in their customers but spotted nothing amiss in this case.

She said they relied on a member of the family or executor to inform them.

However, Nationwide was not able to explain how that would help if someone takes advantage of a dementia patient, as they would be unlikely to tell bank staff what they were up to.