This paper summarises the work to date of Cass Business School and Hymans Robertson LLP in relation to assessing longevity basis risk. This work was commissioned by the Longevity Basis Risk Working Group (LBRWG) and funded by the Life and Longevity Markets Association (LLMA) and Institute and Faculty of Actuaries (IFoA). The LBRWG was formed by the LLMA and IFoA in December 2011 with a remit to investigate how to provide a market-friendly means of analysing longevity basis risk.