The formation of ice particles in the Earth s atmosphere strongly affects the properties of clouds and their impact on climate. However, our basic understanding of ice nucleation and crystallisation is still in its infancy. Despite the importance of ice formation in determining the properties of clouds, the Intergovernmental Panel on Climate Change (IPCC) was unable to assess the impact of atmospheric ice formation in their most recent report, because our basic knowledge is insufficient. In this proposal plans are described to establish a laboratory dedicated to improving our fundamental understanding of ice nucleation and crystallisation. It is proposed to develop a series of laboratory experiments designed to quantify atmospherically relevant processes at a fundamental level. In work package 1 the role of glassy solids and ultra-viscous liquids in cloud formation will be investigated; in work package 2 the rate at which various mineral dusts nucleate ice in the immersion mode will be quantified; the phase of ice that deposits onto frozen solution droplets or heterogeneous ice nuclei will be determined in work package 3; and in work package 4 the laboratory data from work packages 1-3 will be used to constrain ice nucleation in numerical clouds models in order to assess radiative forcings. The instrumentation and modelling experience gained in this five year project will provide a lasting legacy and open doors to new research areas in the future. As an international hub of atmospheric and climate science, the University of Leeds is a unique and ideal institute in which to bridge the gap between fundamental studies and the cloud/climate modelling community.