Ofgem has confirmed an 80.06% rise in the energy price cap, sending the average household's yearly bill from £1,971 to £3,549 from October.
The cap will come into effect for around 24 million households in England, Scotland and Wales on default energy tariffs on October 1, and will remain in place until December 31, when it will be adjusted again.
Ofgem's chief executive Jonathan Brearley warned of the hardship energy prices will cause this winter and urged the incoming Prime Minister and new Cabinet "to provide an additional and urgent response to continued surging energy prices".