A chocolate bar has been made using entirely British ingredients for the first time in nearly a century, with cocoa from not Brazil or Bali, but Berkshire.

Created at the University of Reading, it was named the Reading 100 Chocolate Bar to mark the university’s 100th anniversary.

It is the first of its kind since 1932, when Rowntree’s gifted a six-year-old Princess Elizabeth the only other bar of UK-grown chocolate ever made.

Food security master’s student Maha Khan created the chocolate bar by harvesting, fermenting and processing the Reading-grown cocoa.

While the UK’s chocolate market is worth £10.4bn, it is entirely reliant on imported cocoa.

Maha told the Today programme she made the bar to highlight the challenges facing the cocoa growing industry.

She said: “It is incredible that we can make 100% British chocolate – but in the context of climate change, pests and diseases, there are estimates that 30 to 40% is lost.

“And we’ve seen with these heatwaves, climate change, these problems and challenges are only going to get exacerbated.”

The cocoa was grown at the University of Reading’s International Cocoa Quarantine Centre, a collection of more than 300 types of cocoa plant.

The climate-controlled centre in Berkshire is carefully managed to prevent the spread of pests and diseases between different cocoa-growing regions of the world, while also providing scientists with the opportunity to study the plants.

Maha said it was important to highlight the research being done at centre “which not many people are aware of”.

“It is the primary hub of transfer for 97% of cocoa growing countries,” she said.

“So the coco is quarantined there for two years, and so from those plants that are growing I decided to make this chocolate bar.”

“I harvested the cocoa from the quarantine centre, removed the pulp, the beans, fermented it, which takes about seven to 10 days, then I laid it out in the sun, because we’ve had glorious weather, that helped dry it.

“And from then it was just a process of drying, roasting, and at the university facilities I used the lab to winnow, grind, crunch, blend with the milk and sugar.”

“It’s a lot of work,” Maha added.

Prof Carol Wagstaff, director of AgriFood Futures at the University of Reading, said: “The UK chocolate industry rests on a supply chain that starts thousands of miles away in the tropics of Africa, South America and Asia.

“A resilient global market is crucial to the many smallholder farmers who underpin the industry and find themselves farming in some of the regions most exposed to risks from climate change, as well as to chocolate makers and chocolate lovers in the UK.

“While growing and buying local produce often makes sense for your health, and helps the economy and environment, it is not a universal rule.

“International trade in food can be a good thing, providing economic stability for communities whilst using natural energy resources for production, and we need to invest in research to keep threats at bay.”