This paper provides an analysis of a heat recovery scheme that collects waste heat from the London Underground, a large potential source that produces significant amounts of heat throughout the year. The heat is captured by an air-to-water heat exchanger located within a ventilation shaft of the London Underground, then upgraded using a heat pump and used as a low carbon energy source for a local district heating network. This work introduces some of the key aspects of the technical design of this novel urban heat recovery and delivery system, as well as compares it to similar solutions that recover heat from urban underground railways. The theoretical performance of the system is evaluated and compared to the previous heating method used for the buildings supplied by the network. This paper also provides recommendations for the implementation of future installations for secondary heat recovery and reuse in cities.