This work is a component of the DAPPLE project (www.dapple.org.uk). DAPPLE concentrates on flow and dispersion in the urban canopy. Detailed knowledge of short-range dispersion in UK cities is used to assist emergency response planning and inform models. Some useful information already exists (e.g. data obtained in London within the EPSRC DAPPLE Project and its extensions) but is limited in extent. Recently eight mobile perfluorocarbon tracer experiments were carried out in Central London (United Kingdom). The tracer was released at a constant rate from an instrumented vehicle driven through the Marylebone Road, central London test area on the 13th of March 2008, between 11:00 and 16:30 UTC. The short range dispersion experiments are described including the spatial variation in the line source release, sampling, prevailing and in-street wind observations. The results of the experiments and preliminary analysis are also presented.