The ads state that British Gas has lost nearly 1m customers in the past year.
After Npower claimed to have triggered a 'massive demand' for its services with ads in last weekend's national newspapers, it is to repeat the work over Christmas.
British Gas admitted on Friday that it had lost more than 900,000 customers after a UK gas shortage forced it to raise prices twice in the past 12 months.
Npower has also raised prices, but claims to be 10% cheaper than British Gas (Marketing, 6 October).
This article was first published on Marketing