Mars Inc. Announces Major Renovation of Slough, UK, Factory, Birthplace of Mars Bar

Mars Inc. announced a major, £190 million (about $255.5 million) investment in its historic Slough, UK, factory — the latest part of a €1 billion commitment to invest in its operations across the European Union made in September 2025. The project appears to have already begun, with the announcement mentioning that project investments would occur between 2023 and 2028.

The Slough factory is the birthplace of the Mars Bar, and as that candy bar celebrates 94 years, the plant will be transformed into a next-generation manufacturing hub, the company said. It serves the UK market and exports product to the EU — more than 2.7 million kg of chocolate was sent to Ireland from the factory in 2025, and more than 12.3 million kg to the Netherlands.

Plans for the Slough facility include implementation of robotics and artificial intelligence (AI) with upgraded machinery, and advanced cooling systems and energy-efficient utility improvements as well. Furthermore, Mars will invest in workforce upskilling to prep employees for the future of advanced engineering, automation and data-enabled manufacturing. The company anticipates deploying digital twin technology to optimize production, ensure consistency and reduce waste, it said.

The Slough factory is one of 24 across 10 EU countries operated by Mars Inc., with 25,700 workers producing products sold in more than 100 markets. Mars has invested nearly €500 million over the past five years across its eight factories in France to modernize production and accelerate the environmental transition, the company said. Additionally, the company will pour €18 million into a new milk plant and €16 million in new conches at its Veghel plant in the Netherlands in 2026. And investment in the company’s Janaszówek, Poland, chocolate plant continue, with state-of-the-art automation and a 63% increase in site capacity on the capital spending docket there.