Unilever has abandoned plans to use a traditional slimming extract in a range of diet drinks, throwing Phytopharm, the British-based developer, into turmoil.

The Anglo-Dutch group said Phytopharm's drug - based on the Hoodia plant used by the San tribe in the Kalahari desert to suppress appetite - was "unsuitable" for further development with its SlimFast range, dashing hopes for any commercialisation of one of Phytopharm's pivotal experimental products.