The study, which was commissioned by Energy UK, revealed the market share of the independent suppliers had more than doubled at the end of July this year, up from 3.1 per cent at the same time in 2013.
The quarterly update showed that more than one million customers moved from a large supplier to a small one and the number of companies offering dual fuel deals was at an all-time high at 25.
The report added that there were 19 suppliers selling duel fuel tariffs to households in July, rising from the 18 that were recorded in January 2014.
It stated: “This is now the highest number of suppliers we have seen since we began regularly reporting on supply competition in 2005”.
Energy UK chief executive Angela Knight said the growth of small suppliers was a “clear sign customers are reacting to the range of choice on offer to them from companies large and small”.