Abstract
Considerable excitement was caused in March 2014 by the announcement of a detection by the BICEP2 experiment of gravitational waves in the early universe via their effect on the Cosmic Microwave Background (CMB). These gravitational waves imprint themselves into a particular mode of polarisation of the CMB, and measurement of their amplitude would finally reveal the energy scale at which inflation took place, as well as providing direct evidence that it actually occurred. It would also represent the farthest back in time we could ever look, and the large amplitude as discovered provides a point of contact with string cosmology and other theories of the early universe, and has stimulated much theoretical work following the announcement of the discovery. This talk will look at the background to the experimental results, the theoretical implications of the range of possible amplitudes and also the latest information from the Planck Satellite, which as well as measuring the CMB itself, provides important information on the possible foreground contamination in the results.