Big Six energy suppliers have lost more than a third of their profits over the last year as they keep losing market share to smaller competitors.
EDF, Npower, SSE, Eon and Scottish Power and British Gas, which used to have a near monopoly on supplying energy to households in the UK, saw their share drop to 70 per cent in June, from 75 per cent a year earlier.
It comes as medium-sized suppliers benefited the most from encroaching on the old monopoly, swelling their market share by seven percentage points in electricity and five in gas. Overall they control a fifth of the market.
They also managed to take share from small suppliers, whose market share dropped from 10 to nine per cent, the first fall on record.
Earlier this year several the Big Six warned that a price cap would further eat into their bottom line as Ofgem limited what they could charge some customers.
It comes as a long line of around a dozen small energy suppliers went bust in the last year and a half, often passing on their customers to the medium suppliers.
The data, which comes from Ofgem, also showed that progress on combating emissions has fallen to its lowest point since 2012. Greenhouse gases fell by 2.5 per cent in the last year against three per cent the year before.
Joe Perkins, the chief economist at the regulator, warned that although the country has made progress, there is “much more” that needs to be done to tackle emissions.
“We want the UK to remain a global leader in bringing down greenhouse gas emissions, and our major objective is to help the country rise to the challenge of cutting emissions to net zero by 2050 at the lowest possible price to consumers,” he said.
He added that the regulator will continue to encourage competition in the supply market to benefit customers.
“As well as protecting consumers in the future, our duty is also to protect those today,” he said.