This one-off documentary goes deep inside the Willie Wonka world of Cadbury, Britain's biggest and best-loved chocolate maker. Behind closed doors at the famous Bournville plant, a team of dedicated scientists struggle to meet the biggest challenge the company's faced for a century - to dramatically cut sugar from their Dairy Milk recipe. Meanwhile, the firm's Easter Creme Egg campaign finds Cadbury agents 'reverse shoplifting' as they hide prize-winning white eggs around the country. Elsewhere in the factory new flavours of chocolate are put into production, with wacky recipes invented by lucky members of the public.

• Documentary