614,000 customers switched their electricity supplier last month, according to figures from Energy UK.
That's more than twice the number that switched in October, and the highest number of switches since 2010. Last month saw five of the big six suppliers announce that bills would be rising.
125,000, or over 20 per cent, of those were changing to a company outside of the big six. The data doesn't include those customers who change tariff, but stick with the same supplier.
Angela Knight, chief executive of Energy UK said:
More people are switching energy supplier which is proof that the retail energy market is working well. The sharp increase in the number of people switching between companies and the number of fast growing smaller suppliers shows this is the case.