Almost half a million Brits switched their energy supplier in July – up 23% on the previous year.

But figures from industry trade body Energy UK revealed that 47% of customers switched from a big supplier to a smaller or medium-sized provider.

The news will be a bitter blow for the ‘Big Six’ energy firms – British Gas, EDF, E.ON, Npower, Scottish Power and SSE –  which have seen customers walk away in droves following a series of price hikes in recent months as a result of rising wholesale energy costs.

Centrica-owned British Gas revealed in May that it had lost 111,000 customers accounts in the first four months of 2018, while Scottish Power confirmed 100,000 had left in the first half of the year. Npower saw an exodus of 120,000 in a similar period.

In total, 3.2 million Brits changed energy providers so far this year.

Lawrence Slade, chief executive of Energy UK, said: “It is positive to see that nearly half a million customers switched to a better energy deal in July despite the record high temperatures.

“It has never been a better time to shop around or call your existing supplier to see if you could be on a better deal, whether that’s a cheaper deal or a green tariff or better customer service.

“Switching can take as little as ten minutes and, with the Energy Switch Guarantee in place, customers should feel confident it will be simple, speedy and safe.”

Steven Day, co-founder of Pure Planet, a renewable energy challenger brand, said the ‘Big Six’ business model is broken as operating costs are too high and consumers are being asked to pay inflated prices.

“We now have a market where smaller, cleaner independent suppliers can beat the Big Six hands down on price and customer service.

“Now, more than ever, there is no reason to stay with expensive, dirty energy suppliers.”

Related: See YourMoney.com’s guide to switching energy supplier for more information.