The group's cartoon character Vinnie - a cross between a panda and a dog - was launched last April as part of a relaunch for the Fox's biscuit brand.

And Northern Foods said it was now planning a second series of Vinnie ads to further boost the brand in the run up to Christmas.

Northern, which makes Goodfella's pizza and supplies products to Marks & Spencer, moved to reassure today ahead of its interim results that it was continuing to fully recover soaring input costs through price increases.

It has upped its selling prices by 5.6 per cent on average, which had offset a 1.7 per cent drop in sales volumes.

The increasing popularity of its Fox's brand is helping lead a recovery within Northern's bakery division, with the underlying sales rise cementing a return to sales growth over the past year.

However, the group, which supplies all of the major UK supermarkets, said it had seen total sales volumes slip as it pulled out of "marginal" contracts over the past financial year, although it continued to see growth in branded and own-label business.

Total underlying sales rose 3.9 per cent year on-year in the 26 weeks to September 27.

Leeds-based Northern Foods has been refocusing on faster-growing markets and key brands, last year selling off some operations.

It said interim underlying revenues in its chilled operation grew by 2.4 per cent, driven by the ready meals business.

Northern's frozen food arm, which includes Goodfella's pizza, notched up a 4.1 per cent rise in sales on a comparable basis in the period.

But poor summer weather impacted sales of salads, sandwiches and chilled pizzas, with underlying sales ahead by a more muted 1 per cent.

Northern stressed that profits were set to be weighted towards the second half, with an expected winter and Christmas sales boost for products such as soups and puddings.

Stefan Barden, chief executive of Northern Foods, said the group was making headway despite the "challenging environment" of rocketing input costs.