I am a Reader in Particle Cosmology in the Physics Department of Lancaster University. My research is in Theoretical Cosmology and, in particular, in the physics of Cosmic Inflation. Inflation is a period of superluminal expansion of space that occurred a tiny fraction of a second after the Big Bang. It is responsible for making the observable Universe large and uniform. Also, it generated the small variations (perturbations) in the density of matter that gave rise to the formation of galaxies. These cosmological perturbations reflect themselves onto the Cosmic Microwave Background (CMB) radiation by causing small temperature variations. Models of inflation are based on fundamental physics like quantum field theory, supersymmetry, supergravity and string theory. The characteristics of cosmological perturbations which are observed in the CMB can tell apart models of inflation and, therefore, can constrain fundamental theories. Thus, theoretical cosmologists, like myself, use the Early universe as a giant laboratory to test fundamental physics, well beyond Earth based experiments, like particle accelerators.