British Gas has been criticised, despite announcing a 5% cut in gas bills, which will save the average customer £35 a year.
It is the second gas price reduction in six months by the firm, which says the two cuts together will cut £72 from typical annual bills.
The price reduction will take effect from 27 August.
Critics said the cut was too small. But British Gas said higher pipeline costs had made a larger cut impossible.
Martin Lewis, the founder of MoneySavingExpert, called the cut “paltry” and “trivial”.
The news was also criticised as “underwhelming” by the website MoneySuperMarket, which said the cut should be introduced immediately.
The price cut will affect 6.9 million energy customers either on standard or “fix and fall” tariffs.
It follows a similar cut of 5% that British Gas made in January, after moves by a number of the other “Big Six” energy suppliers.