The research showed that one-in-six (17.4 per cent) dual fuel customers are now with an independent supplier, compared with one-in-eight last year – an average growth of 9 per cent each quarter.
Meanwhile, big six dual fuel market share has dropped by 16.7 per cent since 2011, from 99.3 per cent to 82.6 per cent.
Cornwall Energy director Robert Buckley said: “This data shows one of the biggest shifts to independents in the past 12 months and demonstrates just how much the new players like First Utility have driven engagement and encouraged people to switch.”
The figures revealed that First Utility, the largest of the independent suppliers, now has more than 950,000 customers – one-in-four of all non-big six customers.
First Utility chief executive Ian McCaig said: “So much progress has been made over the last five years as more people have come to realise that paying more than you should for energy simply isn’t right.”
Earlier this week, Morgan Stanley warned that smaller suppliers will find it more difficult to gain customers from the big six over next few years, as wholesale prices recover.