<p>Due to the negative environmental consequences of current land-use, and land’s important role regarding carbon, biodiversity and food security, there is an urgent interest in reforming land-use. Policy objectives for tree planting to sequester carbon and the protection of land to increase biodiversity require land reallocation, which leads to inevitable trade-offs. Here, we evaluate the trade-offs between three objectives for rural land: agricultural/forestry production, carbon sequestration and biodiversity, by calculating metrics for these three objectives on a 500 m grid covering Great Britain. We use a multi-objective optimisation that allows us to explore the full option space of possible land conversions and identify the land allocations that entail limited trade-offs. Our results show that current land-use in Great Britain is far from optimal for any combination of objectives. We identify the locations where carbon sequestration and biodiversity can be substantially improved without compromising overall agricultural production, provided conversions are located carefully.</p>