The UK's largest energy supplier has lost nearly a quarter of a million customers in the first three months of 2016.
Centrica, which owns British Gas - one of the "Big Six" energy companies - said they've lost 1.5% of their residential accounts as a result of consumers switching suppliers.
In this period, Centrica added, it has already cut 800 jobs out of the 3,000 it plans to axe this year.
There are just 39 energy suppliers in the UK, and websites like uSwitch.com which encourage customers to switch to save money - but the Big Six still account for 85% of all energy accounts.
British Gas has cut prices three times since the start of 2015, and lowered gas tariffs in line with other providers - yet consumer groups say wholesale energy prices have dropped by 30-40% and that consumers aren't feeling the difference.
Director of consumer policy at uSwitch.com, Ann Robinson, said: "British Gas has made more price reductions since the start of 2015 than any of the Big Six, but it should go further.
"With wholesale energy prices at their lowest in a decade, British Gas must again lead by example and make further reductions to both gas and electricity tariffs, otherwise its customers may feel short-changed."