Earlier this year, global food manufacturing powerhouse Mars unveiled the latest phase of its £190 million investment in its flagship Slough factory.
First opened by Forrest Mars in 1932, the Berkshire facility has produced some of the most recognisable brands in Mars’ portfolio, including its eponymous Mars bars (which were conceived at the site), Galaxy chocolate, Snickers bars and Maltesers products.
The first phase of the £190 million investment began in 2023 and will continue through to 2028, expanding advanced manufacturing, digital capabilities, sustainability initiatives and workforce upskilling at the Slough site.
The American powerhouse said that £32 million of the total investment is scheduled for 2027 to 2028, building on more than £118 million invested in the UK across its Snacking, Food and Petcare businesses in 2024 to 2025 alone.
Speaking exclusively to Food Manufacture, Mars Wrigley’s UK & Ireland general manager, Adam Grant, explains why the Slough site is so pivotal for the multinational’s European operations.
How vital is the Slough site to Mars UK and European operations?
Slough is an important manufacturing hub for us - it is our second-largest confectionary Factory in Europe and now produces up to 5 million bars a day, doubling our capacity and ability to export to 33 markets.
The latest investment in Slough is part of a wider strategy to modernise and strengthen our footprint across Europe. We’ve invested over €1.5 billion in EU manufacturing over the past five years and committed a further €1 billion through to 2026.
Can you tell us more about the ‘state-of-the-art’ manufacturing capabilities that are being developed at the site (i.e. robotics, AI, upgraded machinery)?
The biggest shift is towards a more automated, data-led production environment across a range of lines on the factory floor. We’re upgrading with new digital systems, robotics and AI, and bringing in Formula 1-style ‘digital twin’ technology. So, we’re combining the character of our 1930s factory with the precision of an F1 pit crew. And what that really means is simple - whether it’s a Mars bar or a Malteser, you get the same quality product every time.
And just as important, we’re investing in our people. Bringing together real hands-on craft and advanced technology, side by side, and doing it in a way that’s guided by our principles - right for both our people and our products.
Why specifically has Mars chosen its Slough facility as the ideal site in which to invest hundreds of millions of pounds to develop a ‘next generation’ hub?
Our Slough site has been at the heart of our Mars UK business for over 90 years. It was the birthplace of the Mars bar when Forrest Mars came to the UK in 1932, and it still plays a major role in our manufacturing footprint today.
This investment is our vote of confidence in the future of UK manufacturing and makes Slough our second-largest factory in Europe. By putting £190 million into our Slough and wider UK operations since 2023, we’re not just modernising a factory, we’re supporting hundreds of high-skilled jobs, strengthening local supply chains, and helping the UK remain a hub for large-scale, innovative chocolate production.
What sustainability innovations are planned to make the facility more efficient and more in line with ecological performance guidelines?
This new technology is designed to reduce variability, improve uptime and support faster decision-making. The result is 50% more efficiency, less waste and millions of consistently high-quality Mars and Snickers bars every day. At peak, lines run at 4,000 bars a minute, more than 40 million a week.
By using a digital twin and more precise process control, we’re reducing variability on the line and making output more uniform. That also helps reduce waste, because fewer changes need to be made later in the process. In terms of waste reduction and energy use, we are also seeing clear improvements here too. The investment builds on our sustainability efforts at Mars and is part of our ambition to cut our greenhouse gas emissions 50% by 2030 and our aim to reach net zero by 2050.
The investment is making the factory more energy‑efficient and less waste‑intensive. Upgraded machinery, advanced cooling systems and modernised utilities reduce energy use, while digital tools improve precision and consistency in production, helping to minimise waste across the site.
How strategically important is the UK for Mars global manufacturing operations?
The UK is one of our largest markets and a major driver of growth for Mars. In 2024–25 alone, we invested more than £118 million across our UK Snacking, Food and Petcare businesses, reflecting our long-term commitment to the country.
Our latest investment in Slough builds on that momentum and demonstrates our confidence in the UK as a place to manufacture and innovate. It’s part of our wider ambition - globally - to create a manufacturing network that is more modern, resilient and ready for the future.
Are you able to give us a rough breakdown of the remaining £32 million in investments planned for 2027 to 2028?
For this next phase, we’re focusing our funding on major machinery upgrades and logistics transformations. This includes installing next-generation production equipment and modernising our inbound and outbound logistics networks to drive maximum efficiency
The Slough facility is an important employer for the local region – what impact does Mars envisage the implementation of AI will have on human employment at the site?
Upskilling our Associates and equipping them with the tools they need for the future is central to the investment. Alongside new technology, we’re investing in our workforce, ensuring that all Associates who work there have the skills they need to work with the new machinery and digital systems as manufacturing evolves.
We’re creating clearer pathways into areas like advanced engineering, digital operations and data-led manufacturing, while giving people the training to move into those roles. A structured seven-week training programme is in place to support that transition, so this is as much about investing in our employees and their future.
