Didcot is junction of the routes to London , Bristol , Oxford and to Southampton . That meant that the town had strategic importance to military logistics , in particular during the First World War campaign on the Western Front and the Second World War preparations for D-Day . Didcot 's junction of the routes to London , Bristol , Oxford and to Southampton via the Didcot , Newbury and Southampton Railway ( DN&S ) made the town of strategic importance to military logistics , in particular during the First World War campaign on the Western Front and the Second World War preparations for D-Day .