The watchdog's findings revealed that it received 49 per cent less contacts from the provider's customers between October and March when compared to the same period 12 months earlier.
Overall, customer contacts about the 'Big Six' providers fell by 33 per cent, with calls concerning ScottishPower also decreasing by 29 per cent.
Audrey Gallacher, head of company performance at energywatch, said: "Consumer contacts about energy suppliers have fallen overall, largely due to the ongoing recovery of British Gas from its customer service meltdown in 2006/07."
In its recent interim management statement released last week, British Gas also stated that it has improved its customer service.
The supplier stated that complaints to energywatch about its service fell by 78 per cent in the first few months of 2008 compared to the same period last year.
It was also announced that the provider improved its call answering time by over 60 per cent.
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