SHAREHOLDERS at British Gas will demand today that the company pays back its part of £2.5 billion energy companies made from overcharging their costumers in 2015.

Britain’s largest energy provider Centrica, which owns British Gas, will be meeting in London for its yearly AGM and ethical investors in the firm will be quizzing managers over allegations that customers were “extorted and bullied.”

The company’s introduction of pre-payment meters has been described by households as “predatory,” with customers having installations forced upon them by British Gas engineers.

According to campaigners Fuel Poverty Action, the policy has mostly affected the poorest and most vulnerable.

A British Gas customer told the group she was woken up by gas meter fitters one day, holding a court warrant to put a meter outside her bungalow.

She said: “They could plainly see I could not walk well and that I had a walker and a crutch and a wheelchair.

“They started asking the neighbours if I could walk OK and telling them I how much I owed.

“They left me screaming and crying and having an asthma attack. When the gas goes I will have no gas at all.

“They have defrauded the court because they never informed the judge that I was disabled and ill.”

Last year, the Competition and Marketing Authority found that Britain’s largest suppliers, known as the Big Six, have raked in an average of £1.7bn a year through “excessive prices” since 2012.

And that haul rose by nearly 50 per cent in 2015.

Pre-payment meter users were particularly affected, paying an extra £260 to £330 each a year compared to direct debit customers.

Fuel Poverty Action spokeswoman Ruth London said: “After a year that saw record numbers of winter deaths, we have the spectacle of British Gas celebrating their latest bumper profits.

“British Gas is abusing its power to systematically extort money from a huge swathe of the population, and in particular the most vulnerable.”

Campaigners are also expected to give CEO Iain Conn a tough time after he was paid a whopping £3 million salary last year.

British Gas had not responded to a request for comment as the Star went to press.