According to a new report, the big six energy firms in the UK received a total of more than 5.5 million complaints in 2013, which was the first full year of official figures.

Which? has launched a new campaign to address issues in the energy market. The campaign group is urging people to sign a petition to address issues. The biggest energy firms, British Gas, EDF Energy, E. On, Npower, Scottish Power and SSE received a total of 5,579,665 complaints during the year 2013.

The issue range from bills, metering, customer service and switching, through to payment. Npower received the highest number of complaints among the six of the biggest companies, with 1,383,650 complaints. It was followed by EDF with 1,240,005; British Gas with 1,235,550; Eon with 929,230; SSE with 482,582; and Scottish Power with 308,648 complaints.

Big Six firms account for 97% of the market and the high number of complaints shows that the industry needs reforms to address service issues and improve customer experience. Which? is urging the government the regulator, competition authorities and the energy companies to implement reforms in the sector.