UK lotto sales have fallen by 60% from its heyday in 1996 (just two years after the introduction of the game) when weekly sales were close to £100m, to £40m per week in nominal terms by 2013 (and, with inflation averaging 2.9%, the real fall in sales revenue was approximately 75%). The aim of this paper is to estimate the demand for lotto - so as to understand the fall in lotto sales revenue, and to evaluate attempts since 2013 to arrest the fall.