The London 2012 Summer Olympic Games (SOG) was one of the largest in history and presented London with the biggest travel demand challenge ever experienced in a western world “mega city”. Some 20M additional visitor trips were expected in a city which is already considered to be widely congested. In addition a dedicated transport system for the Olympic Family (athletes, media and officials) of some 55,000 people (also the largest in history) required removal of some 108 miles of roadspace for the Olympic Route Network in some of the city’s most congested locations. Research and practice demonstrates that Travel Demand Management is an essential requirement for managing travel demand challenges in congested cities facing increased travel demand of this scale. In congested high demand contexts TDM acts “to reduce the number of vehicles using the road system while providing a wide variety of mobility options to those who wish to travel”. In the Olympic context critical strategies involve influencing the mode and time of travel and in particular, acting to reduce ‘base load’ travel demand to enable greater capacity to cater for special event travel. For the London 2012 Games there was a requirement to reduce the base load on both the road network and the transit system. The London 2012 TDM program was the largest ever developed for a specific event. Costing some £30M it included TDM planning for businesses representing over 611,000 employees, new web tools for trip planning of over 63M trips and some 107M travel advice emails. The paper presents an ‘independent’ review of the TDM program adopted for the 2012 SOG. An independent perspective allows us to discuss aspects of the program which are sensitive for authorities/Government yet are essential in understanding real performance and outcomes. The paper outlines the official strategy adopted but also includes a review of less widely acknowledged features of the ‘big scare’ and how this effect was manifest during London 2012. It then reviews the impacts demonstrated on the scale of travel in London using a synthesis of reports during the games, an assembly of available official statistics and a series of independent business monitoring studies undertaken by the researchers during the games. The paper commences with a review of the Research Context, including a short review of the research literature on TDM and large special events, an outline of the London 2012 games and its TDM program and a discussion of ‘the big scare’ and how it is thought to have been apparent during the games. TDM impact data is then summarised including a summary of pre-games/games time reports, a summary of available official data and a summary of the impact of business surveys undertaken as part of the research. The paper concludes with a discussion of key lessons learned for futures games and for managing congestion in cities generally. London is already well known for use of TDM notably the road ‘congestion pricing’ scheme in use in central London. The focus of this research is on the Olympic games rather than the Paralympics.