Cadbury has sold nearly ten million Wispas since the bar was revived due to popular demand, earlier this month.
Workers are said to be working at a “feverish” pace at the Bournville plant where the bar is being made.
It was seen as an icon of the 80s by the internet generation who campaigned in their thousands to bring in back, on sites including Facebook and MySpace.
Spokesman Tony Bilsborough said: “At a time when there’s so much doom and gloom around the manufacturing sector, we’re pleased that Bournville seems to be bucking the trend. Wispa is flying off the shelves and is one of the best-selling bars in the country.”
The company is also celebrating after sweeping the boards at the PR Week awards. It was lined up for the digital innovation category award, because it was online audiences that called for its return, but was also given the top campaign title for 2007.
Wispa bars first emerged in 1981. TV adverts included Yes Minister’s Paul Eddington and Nigel Hawthorne, Victoria Wood and Julie Walters and Hi-De-Hi’s Simon Cadell and Ruth Madoc.
Sales began to fall in the 1990s and it was discontinued in 2003.
The bar returned to permanent sale on October 6 for 45p, compared with its original cost of 16p.