'Is a Pendulum's Motion Predictable?', 'Lunch-Hour Lecture', University College London, 21 October 1986 Contents of Lighthill's folder labelled with lecture title as above: brief correspondence, programme of 'Lunch-Hour Lectures', typescript draft of lecture by Lighthill titled 'The recently recognised failure of predictability in Newtonian dynamics', with manuscript revision, etc. Lighthill lectured on 'The recently recognised failure of predictability in Newtonian dynamics' at a Royal Society / British Academy Discussion Meeting, March 1986 (see L/48-L/54). 1986