The most important tool for studying the Universe on the largest scales has been the Cosmic Microwave Background (CMB) radiation. CMB polarization provides a new window on the early Universe and will provide constraints on inflation via gravitational waves. However, the success of future CMB experiments lies in the improved understanding and removal of foreground emission from our own Galaxy. The first part of the project lies in developing our understanding of diffuse Galactic radiation through observation and modelling. This information will be used in simulations and for improving component separation algorithms and for optimising the design of future CMB space missions. A joint analysis of the forthcoming Planck data, combined with state-of-the-art low frequency foreground surveys will be made, to give the most precise CMB power spectrum from Planck.The future of cosmology at radio wavelengths lies in the mapping of the hyperfine 21cm line of neutral atomic hydrogen (HI). This is one of the key science drivers for several future radio telescopes including the Square Kilometre Array (SKA). Measuring the distribution of HI as a function of redshift will revolutionize cosmology, including dark matter and dark energy. However, like for the CMB, a major obstacle will be Galactic foregrounds, which are at least 3 orders of magnitude brighter than HI. Many of the techniques used for the CMB can be used in HI mapping, including the study of Baryon Acoustic Oscillations (BAO). We will make simulations of HI and foregrounds to study how well the HI signal can be extracted by employing techniques used for CMB data. Guided by these simulations, we will analyze data from telescopes that are soon to come online (e.g. MeerKAT, ASKAP). We will also look to develop new instrumentation to detect BAO such as the Baryon acoustic oscillation with Integrated Neutral Gas Observations (BINGO) experiment. The ultimate goal will be to detect BAO using one of these approaches.