<p>Crop wild relatives (CWR) contain an important reservoir of genetic material for use in plant breeding and can provide increased resistance to biotic and abiotic stress, contributing to improved food security. Systematic in situ conservation of CWR is limited by the lack of population-level genetic diversity studies and the development of management and monitoring strategies from their results. We present the first systematic genetic analysis of multiple CWR for in situ conservation planning by investigating the suitability of The Lizard Peninsula, Cornwall, UK (‘The Lizard’) as a location for the first of a complementary network of UK CWR genetic reserves. It also provides a baseline of genetic data for future monitoring and management recommendations resulting from the genetic analysis. AFLPs were used to perform a genetic diversity study on eight CWR on The Lizard, Cornwall and across the southwest of the UK. CWR on The Lizard held as much genetic diversity as populations from other southwest UK sites. Further, this diversity was largely distinct from southwest populations, indicating The Lizard as a suitable location for in situ conservation of UK CWR diversity, while also revealing that The Lizard is not, on its own, sufficient to conserve the genetic diversity of all CWR in the southwest. This highlights the need for a network of complementary UK genetic reserves with targeted, long-term management informed by genetic diversity data, and represents a model that can be applied globally.</p>