The alert comes weeks ahead of the Ofgem price cap hike from January 1 after Christmas, which will add £21 to bills.

Ofgem announced its latest price cap on Friday morning, with average energy bills to increase by 1.2 per cent from January to £1,738 a year.

UK households face bills rising in January, as part of a new Ofgem energy price cap which will take bills up by £21 on ...