Jan is former chief economist of Arup, where he led work on the London infrastructure plan and many transport projects. He is chair of the Central District Alliance and Hatton Garden business improvement districts. Jan is chief economic adviser to the London Property Alliance (City and Westminster property associations) and is an independent adviser to the EC BID in the City of London. He is currently writing a biography of Lord Ashfield (1874-1948), the creator and first chairman of London Transport.