BLUNDERING electricity chiefs estimated shocked grandparents Nigel and Linda Brotherton had run up a massive electric bill of more than £500million.

Then they sent the couple a bill saying that to pay it off their monthly direct debit would be increased from just £87 to a whopping £53.5million.

The Brothertons, who live in Roughlee, were told they didn’t need to do anything because the money would be taken automatically from their bank.

But accountant Nigel, 62, said: “There was just one problem with that – I didn’t quite have £53million in my current account at the time.”

The problem arose after the Scottish Power electricity board installed a new meter at the couple’s 16th Century cottage home.

Their electrician connected one of the wires the wrong way round so that instead of recording the number or units used it didn’t register any and continued showing zero.

Nigel and Linda, 59, say that they did not notice because they paid their bill by direct debit each month and were never asked to give a reading.

But after they recently switched suppliers to npower, a man was sent round to read their meter.

When he entered a reading of 'zero', npower’s computer wrongly assumed the dials must have gone all round the clock – and automatically flagged up the huge bill.

Bizarrely, though, the online bill also showed that the couple had actually overpaid and were in credit by £1,362.69.

But despite repeated phone calls to npower, and contacting the regulator Ofgen, the couple are still waiting for a refund and written confirmation they won’t have to fork out the £53,480,062.00 a month. Father-of-two Nigel said: “It’s a good job they didn’t actually try to take all that money from my bank account.

“Not only would it have gone way over my overdraft limit, but it could have brought down the bank. The electricity board have admitted it is a mistake and told us we don’t need to pay the money but we are still waiting for the refund they owe us.”

Infamous Alice Nutter, one of the notorious Pendle witches who was hanged 400 years ago, is reputed to have once lived in the couple’s cottage.

Nigel added: “Perhaps she put a curse on the meter. But if the electricity board doesn’t sort this out quick I’ll get her to put a curse on them.”

A spokesman for npower apologised and said: “This was clearly a mistake.

“Mr Brotherton’s meter was incorrectly wired by his previous supplier and not npower, which had a knock-on effect to how we billed the account. His payments are set at £87, so no extra money will be taken and we have processed a refund which should be with Mr Brotherton soon.”