Cadbury is to bring back the Wispa chocolate bar for good after a campaign on social networking websites demanded its return.

The chocolate firm said 20 million bars were sold in seven weeks during a trial run last year.

The project to bring back the aerated chocolate bar has seen thousands join groups on sites such as Facebook and MySpace dedicated to its return.

Cadbury spokesman Tony Bilsborough said: “Wispa is a true icon loved by its fans everywhere. We brought it back temporarily to see if the desire was genuine, but fans are still rallying so we took the decision to bring it back for good.

“We know others have looked at Wispa and tried to copy its success by bringing back other brands, but we don’t believe anyone has managed to recreate the same excitement.”

The bar will return to permanent sale on October 6 and cost 45p. It originally cost 16p.

Wispa bars first emerged in 1981 for a trial in the North East. The bar with a bubbly centre was seen by many as a rival to Nestle’s Aero bar with the slogan “Bite it and Believe It”.

Television 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 as Cadbury concentrated on other brands.

Last week, Cadbury revealed it had posted a 46 per cent leap in first-half profits and said it would take “whatever measures necessary” to combat commodity cost rises.

Strong demand for brands such as its Dairy Milk chocolate and the new Creme Egg Twisted Bar helped drive the rise in underlying pre-tax profits to £223 million, said Birmingham-based Cadbury.

But the group, which spun off its drinks arm in May and dropped the Schweppes brand from its name, said it was stepping up its cost-cutting efforts to tackle challenging conditions and price increases.

Cadbury has already upped its prices by three to four per cent in the past year, and they will be looked at again as part of a business review to ensure it meets goals to grow revenues by four to six per cent and achieve “mid-teens” profit margins.

Staff numbers will also be reviewed, the group confirmed.

Cadbury chairman Roger Carr said: “Against a background of more challenging economic conditions, we will take whatever measures are necessary in costs, prices, organisation structure and business portfolio to underpin and deliver the performance commitments we have made for 2008 and beyond.”

Sales in the first six months of the year were ahead of the group’s targets, up 7.3 per cent on a like-for-like basis.