Earlier this week, small supplier GB Energy had to cease trading citing "difficulties relating to rising wholesale energy costs".
Safeguards put in place by Ofgem ensured customers and their credit were passed to Co-op Energy as the Supplier of Last Resort.
Some of the big six suppliers however, have increased fixed prices whilst freezing standard variable tariff rates to try and alleviate this pressures from wholesale costs.
Five out of the big six energy suppliers have increased the price of their most competitive fixed rate tariffs by an average of £129 since September — E.ON has risen fixed deal prices the most, hiking its cheapest plan by an eye-watering 35% or £255 a year, from £760 to £1,015 since September.
This means that those who switched their energy a few months ago to a big six supplier, were likely to have been offered a better deal than is now available — smaller suppliers are once again offering the most competitive deals.
SSE, British Gas and now E.ON, have now announced they will freeze the price of their standard variable tariffs for customers.
Claire Osborne, Uswitch energy expert warns: "Standard variable tariff price freezes may look good on paper, but in reality could lull consumers into a false sense of security.
"The fact remains that consumers on standard deals could be overpaying for their energy by an eye-watering £200 a year. These customers should switch to a competitive fixed rate tariff, which also gives protection for longer against any future price rises."
Some smaller suppliers have decided to increase the price of their standard variable energy tariffs: these are the variable energy plans that are the default for suppliers when customers have ended their fixed deal term or they've never switched.
The suppliers that increased their standard rates are: Ovo, Co-operative Energy, GB Energy, Ecotricity, Octopus Energy, Flow, So Energy and Bulb — collectively by an average of 9% or £79 a year since September.