Our research group studies Active Galactic Nuclei at radio frequencies using Very Long Baseline Interferometry, a technique which combines data from multiple radio telescopes that can be seperated by very large distances. With the high resolution provided by these large baselines the inner regions of relativistic jets emanating from the cores of AGNs can be studied. Our group uses the US-based VLBA to observe these regions at multiple polarisations. This polarisation data can then be used to probe the magnetic fields in the vicinity of the relativistic jet - in particular polarisation features such as spine-sheath structure and Faraday rotation can yield valuable information about jet behaviour. Recent work by our group includes studies of the effects of finite resolution on Faraday rotation structure, the observation of reversals in the direction of Faraday rotation measure gradient across AGN jets and the development of Maximum Entropy Method based deconvolution software to image jet polarisation.