Millions of people face higher energy bills from September after Scottish and Southern Energy followed Scottish Power and British Gas in raising prices.
SSE is to increase gas prices by an average of 18 per cent and electricity prices by 11 per cent from 14 September. The increase will mean a typical annual, dual-fuel bill will rise from £1,094 to £1,265, an increase of £171.
The firm owns Southern Electric, Swalec and Scottish Hydro. It said its decision reflected higher wholesale gas prices, a higher cost of using energy networks and the cost of environmental schemes.