Statement from CEO (British Gas being part of Centrica) here:-
https://www.britishgas.co.uk/media/r/1486/why_we_ve_had_to_raise_electricity_prices_-_our_f
Centrica Annual Report for 2016 here:-
https://www.centrica.com/investors/financial-reporting/2016-annual-report
From the FT:-
Centrica, the parent company of British Gas, insisted it had been making a loss on the supply of electricity to UK homes for more than a year as it announced a 12.5 per cent price increase for 3.1m domestic customers from the middle of next month.
It
blamed the rising costs of government energy policies, such as subsidies to support wind farms and solar projects, for the electricity price increase for customers on its standard tariff — the most common rate. These costs, plus network charges, had increased 16 per cent since 2014, the company said.
"We are living in very strange times, and they are likely to get a lot stranger before we bottom out"
Dr. Hunter S Thompson