Exclusive: Haul of illicit products led by medicines regulator was described as world’s largest of its kind, but no arrests have yet been made

Wedged between an air-compressor service and an auto repair shop on a Northampton industrial estate is an undistinguished red-brick unit that was, until recently, the base for a major illegal weight-loss drug operation.

In late October, enforcement officers arrived here for a two-day raid, seizing thousands of unlicensed Alluvi-branded weight-loss pens, raw chemical ingredients, manufacturing equipment, packaging materials and £20,000 in cash. Some of the pens were labelled as containing retatrutide – a powerful GLP-1 agonist still in clinical trials, unapproved for medical use but widely hyped online as the next Mounjaro.