Millions of consumers on a 'green' tariff say they will claim back up to a decade of premiums paid on their energy bills, in response in the latest greenwashing scandal.
A study, of 2,000 adults, found 83 per cent of all customers on a green plan don't fully understand what they are paying for.
Most are unaware they are already paying for green energy via taxes already baked into their energy bills.
And while more than half of those on a tariff advertised as 'green' believe the energy they receive is 100 per cent renewable, 55 per cent still have no idea where or how it is generated.
A third of those on a green tariff say they chose it to offset their guilt about the way they use energy.
However, 61 per cent said they would take action if they were to discover their energy company had misled them with regards their green claims.
Archie Lasseter, Sustainability Lead for energy company Utilita, which commissioned the report, said: "The results of this survey show us that customers care deeply about their environmental impact and want to make a difference.
"Allowing regulation that results in customers being misled cannot prevail. The loopholes which have led to greenwashing must be closed, urgently.
"Government policy has completely overlooked the first step in tackling climate change - reducing energy waste, which is what our Smart Score technology enables homes to do"We have proven that, on average, households can reduce their energy wastage by up to 20 percent if they are given the intel to do so - right now, most of our customers are using around 11 percent less than the average household."
Over a quarter of energy customers on a 'green' tariff claim to be paying a premium compared to the cost of a standard tariff (26 per cent), with the average premium being around 12 per cent.
That's approximately £144 per year more, based on the UK's average £1,200 energy bill.
The study, conducted via OnePoll, also revealed long-standing customer loyalty may finally come under strain, as most (74 per cent) energy customers on a 'green' tariff said they would leave their current energy company if inaccurate claims about the energy supplied to them had been made.
Consumer law expert Matthew Unsworth has a special interest in consumer rights associated with greenwashing, and he added: "There is no specific anti-greenwashing legislation in the UK.
"Having said this, many misleading environmental claims will fall foul of the restrictions contained in the Consumer Protection from Unfair Trading Regulations 2008.
"In particular, instances of greenwashing are likely to contravene Regulation 5, which prohibits false and misleading commercial practices, or Regulation 6, which prohibits commercial practices serving to hide or obfuscate material information.
"It is worth bearing in mind that a deceptive eco-claim will only constitute an offence under either regulation if it causes or is likely to cause consumers to enter into a transaction when they would not otherwise have done so."
