One in seven food businesses on major delivery platforms, including Deliveroo and Just Eat, is now a “dark kitchen”, a university study shows.

The findings, which shine a light on the scale of the hidden takeaway industry, found that 15% of all online food retailers in England were dark kitchens.

Also known as “cloud”, “ghost” or “virtual” kitchens, they are delivery-only with no customer-facing storefront.

Despite rapid growth, they have – until now – lacked a clear and consistent definition, creating challenges for regulators, local authorities, food safety officers, industry stakeholders and consumers.

Dr Lucie Nield, co-lead investigator from the University of Sheffield, said: “People deserve greater transparency about the food they are ordering online, and these businesses must be held to the appropriate regulatory standards.

“Without this, dark kitchens risk falling through the gap, with potential consequences for public health, particularly by encouraging increased use of online takeaways, greater availability and therefore greater consumption of high fat, salt or sugar food.

“Dark kitchens have previously been poorly defined and under-researched, making their impacts difficult to fully understand.

“Adopting a shared definition is essential for clearer communication, more effective regulation and inspection and for driving public health agendas.”

A dark kitchen on an industrial estate in south London. The sites can help companies lower their operating costs. Photograph: Anna Watson/Alamy

The study, which was commissioned by the National Institute for Health and Care Research, brought together multiple university teams to establish the first industry-wide framework for defining and identifying dark kitchens.

Researchers worked with academics, public health professionals, local authorities, national governing bodies, industry workers and consumers to ensure the definition reflected how the businesses operated.

The final wording was: “Technology-enabled commercial kitchen(s) operating primarily for delivery, to fulfil remote, on-demand, consumer online orders of food for immediate consumption.”

The academics also examined the scale of dark kitchens on major delivery apps.

Using data-scraping methods across platforms such as Uber Eats and Deliveroo, they identified clusters of food brands operating from the same postcode, a key indicator of delivery-only hubs.

The study also cross-referenced locations using tools such as Google Maps, highlighting how difficult these businesses can be for consumers and regulators to spot.

Although dark kitchen models offer commercial advantages, including lower operating costs and flexible locations, the research highlighted potential implications for public health.

Unlike traditional takeaways, which can be regulated by local authorities using spatial planning policy, dark kitchens are far less visible.

Management zones around schools, which are designed to limit the density of takeaways and support healthier food environments, do not apply to dark kitchens and may be undermined by their activities.

Researchers also raised concerns around food safety and transparency, particularly for customers with allergies or dietary sensitivities. Because multiple businesses can operate from the same kitchen space, consumers may not always be aware of shared preparation environments or potential allergen cross-contamination.

A survey in 2023 found that 40% of participants bought a takeaway at least weekly, commonly via delivery apps and mainly as a treat or for convenience.

Awareness of dark kitchens was low, with only a quarter having heard of them and just 9% knowingly using one. However, after reading a working definition, more than half said they would consider buying from a dark kitchen, though most wanted this to be made explicit.

The new industry-wide definition is aimed at bringing delivery-only hubs under stricter planning and public health oversight with clearer regulation, inspection processes and consumer understanding.