Approximately 29,000 ha of grass buffer strips in the UK have been established under Agri-Environment Schemes with the objective of mitigating intensive arable management practices that have negatively impacted on invertebrate and plant biodiversity. However, typically these strips are floristically poor and as such offer limited biodiversity value. This study aimed to identify management practices to enhance the biodiversity value of existing grass-only buffer strips on three farms in Southern England. An initial scarification to create germination niches was applied in combination with a wildflower seed mixture. The effectiveness of a graminicide (fluazifop-P-butyl) for controlling the competitive dominance of grasses at different rates and timings was also investigated. Responses of wild flowers and grasses, insect pollinators and spiders were monitored for up to four years after establishment. The combination of scarification, sowing and graminicide resulted in the highest cover, species richness, and diversity of wildflowers, and greatest sward heterogeneity. The benefits of establishing sown wildflowers within the existing buffer strips were highlighted by the positive responses observed for both insect pollinators and spiders, and is likely to reflect greater foraging resources and prey availability respectively. A glasshouse study was also conducted to investigate pre- and post-emergent fluazifop- P-butyl applications on the wildflower species in the seed mixture, and demonstrated no long-term effects following application at the recommended rates for buffer strips. The results of the field and glasshouse studies demonstrate that managing existing grass buffer strips with a combination of scarification, sowing and graminicide, can significantly enhance biodiversity. Further studies at a national scale are essential to convince farmers and policymakers of the widespread applicability and reliability of this approach. If this is achieved then incorporating these management tools into future agri-environrnent options could deliver benefits to pollinating insects, spiders and other components of biodiversity. vi.