The 'Big Six' and the UK's other energy suppliers are bracing themselves for the biggest ever investigation into the energy market by Ofgem.
A comprehensive investigation is set to be conducted by the Competition and Markets Authority into claims of collusion and profiteering and will take around 18 months to complete.
Ofgem chief executive, Dermot Nolan, said: "This will help build consumer trust and confidence in the energy market.
"Now is the right time to refer the energy market to the CMA for the benefit of consumers.
"There is near-unanimous support for a referral and the CMA investigation offers an important opportunity to clear the air."
The energy watchdog has issued a number of warnings to energy suppliers over the last few months and with new research showing the number of complaints at an all time high has finally decided enough is enough.
Figures from consumer watchdog, Which?, have acted as somewhat of a tipping point. Last week, the group's research revealed complaints about energy firms was up to a staggering 1.7m in the first quarter of 2014. A 15% leap on last year.
Npower had the highest level of complaints, with an average of 83 per 1,000 customers.
Which? executive director, Richard Lloyd, said: "Yet again millions of customers are being let down by poor service from the Big Six energy companies. This has to change.
"If they want to improve the low level of consumer trust in the energy market, suppliers must up their game now, rather than wait for the results of a competition review."
Earlier this month Ofgem criticised 'Big Six' suppliers for not passing on savings from the reduced price of wholesale energy and under this investigation the firms now face the risk of being broken down into smaller entities or facing massive fines.
Energy UK chief executive, Angela Knight, is confident the investigation will shed a positive light on the energy firms.
She said: "The competition inquiry will allow us to put to bed the toxic debate and shine a light on the progress the industry has already made.
"There are now more companies than ever in the market, switching is on the up especially to smaller suppliers and the industry is making it easier than ever for customers to engage with their company."
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