A 90-year-old dementia sufferer had a ‘dodgy’ smart meter that never worked for eight years after the death of his wife, his family told MailOnline today.

At one point the Surrey pensioner’s monthly direct debit went from £70 to £260 as a result of inaccurate estimates and EDF have been forced to apologise and refund him £700.

Lydia Joseph is devastated that her grandfather David, a retired horticulturist, overpaid for his energy because of ‘extortionate’ and ‘unfair’ bills.

She had discovered his smart meter failed to send any regular readings to EDF from the moment it was first installed around eight years ago. A new working one was only installed a few weeks ago.

She said: ‘He’s paid over the odds. They know he has been living on his own for 10 years, he’s had a dumb meter but no one has done anything about it and they just took his money.’

There are believed to be around 36 million smart meters in Britain – roughly half of all households – but experts believe around 3.5million of them are faulty.

Ms Joseph, who has power of attorney over her grandfather, fears there could be thousands of other vulnerable people who have suffered in the same way due to problems caused by the French energy giant.

It has taken a huge amount of time and energy to bring the complaint to a conclusion with one relative flying from Spain to Surrey to be with David when EDF finally changed his smart meter last month.

The offending EDF smart meter, which the family of a vulnerable 90-year-old claim never worked

Lydia as a child with her now vulnerable grandfather David, whose surname is not being published by MailOnline to protect him from scammers

She told MailOnline: ‘His original smart meter was never successfully commissioned and had therefore been in dumb mode the entire time. It was eight years before they finally replaced it for him last month.

‘It was only when I noticed the huge increase in his payments that I began unravelling all of this and I would say that between my aunt, myself and his carers, we have spent 40 or so hours between us just trying to get this sorted for him’.

David had a smart meter installed in 2015 or 2016, after the death of his wife.

As his health faltered EDF sent engineers to take readings until 2020 when the pandemic stopped the visits, his family says.

From then until 2023 all readings were estimates, due to the smart meter still not working, Ms Joseph claims.

The problems got worse when David was amongst the EDF customers who suffered when a ‘system error’ caused energy bills to soar to eyewatering sums of money.

Customers claimed at the time they were told by EDF that their overcharging issues were related to a switchover onto a new system called Kraken.

Some saw their direct debits soar by 1,000 per cent. Others lost out on mortgages due to affordability problems.

At one point David’s direct debit trebled from £70 to £260, despite being classified as a vulnerable person.

‘When they migrated him to the new system in 2023 his direct debit more than trebled. There should have been some sort of flag raised to query it’, Lydia said.

Lydia, pictured with her grandfather. She says EDF have resolved the case but fears others will be in the same situation

EDF are understood to have refunded £700 plus a credit of £75 to David, whose surname is not being published by MailOnline to protect him from scammers.

Lydia said: ‘That meter looked like a smart meter. It had all the flashing lights and looked like it was working but it was simply in dumb mode.

‘In September, a new meter was finally installed and showed David was spending absolutely nothing on his energy’.

EDF have apologised and said the case is closed.

‘We’re sorry to hear about the problems [the customers] have been facing. We remain committed to helping as many customers as possible, including providing debt relief and installing energy efficiency for those in fuel poverty’, a spokesman said.

At the start of 2022, the then Tory government introduced annual minimum goals for introducing smart meters.

The targets came as part of a wider bid to reduce energy usage and help consumers save money amid historically high bills.

More than 33million smart meters had been installed in homes and small businesses across the country, as of June 2023, the energy watchdog said. This makes up 58 per cent of all meters in the UK.

Greg Marsh, household finance expert and CEO of AI money-saving tool Nous.co, said: ‘EDF slammed a vulnerable, elderly man with extortionate, inaccurate bills.

‘He has been seriously let down by his supplier, who charged him for energy he never used.

‘This goes to show – energy companies are failing customers who need help the most.

‘They must ensure that smart meters are actually working as they should, offer decent customer support when problems arise, and pay back customers who have been wrongly charged without question.

‘It’s not just dodgy smart meters that are the problem – this is yet another example of a broken energy market.

‘Customer service standards have plummeted. Competition in the market is completely dead. And it’s the most vulnerable who are being hit hardest.’