Consumer group Which? has labelled the UK energy market as "broken" and has called for radical reforms after it was found that nearly 5.6m customers complained about the so-called 'Big Six' energy providers last year.Which? has identified six "fixes" to improve the energy market for consumers, calling for an increase in competition, transparency, people power, cost control, customer trust and an improvement in the government's Green Deal.The group has urged the Office for Fair Trading, energy regulator Ofgem and the Competition & Markets Authority to refer the market for a full competition investigation."Millions of people are unhappy with the service they receive from the suppliers which, combined with low levels of trust is yet more evidence that more must be done to fix the broken energy market," said Which? Executive Director Richard Lloyds.He said that a reform of the energy market will give "hard-pressed consumers the confidence that they are paying a fair price".According to recent figures, Npower received 1.4m complaints in 2013, the most out of all the Big Six providers. EDF and Centrica-owned British Gas both received around 1.2m, Eon received 0.9m, SSE received 0.5m while Scottish Power receive 0.3m.Which? Said that the Big Six together account for 97% of the total energy market in the UK."The type of customer complaints that the companies receive ranged from issues with bills, metering, customer service, switching through to payment," Which? said.BC