Geoffrey was already well-established in the Economics and OR group of London Transport when I joined as a new graduate in 1974. His greatest influence on me came when I went to ask his advice on a statistical test. It wasn't his comments on t-testing that created  lasting memory (authoritative as they were) but his willingness to put his own urgent and demanding work to one side for the time it took to help me out of my difficulties. I have told many people about that since, as an example of the sort of behaviour we should all aspire to, and a seminal influence on my view of workplace ethics. In all the years we worked together, and subsequently as we kept in touch over the years, I never knew Geoffrey to be anything other than generous, thoughtful and kind.