The prices went up in the last rise because of the move in the ceiling.
Which had to happen because the people who you pay bills to make a very small margin and if they can't avoid making a loss, they'll stop selling you electricity.
Prices started going up long before that. Producers have been making huge profits.
Understand that the producers are not the UK energy retail providers. They are the likes of BP and Shell. The product they sell is in high demand and therefore they make large profits. That's just economics.