Elgar was right when he said he had a tune that "would knock 'em, knock 'em flat". He set it within his first Pomp and Circumstance march, and it was an instant hit at its 1901 Proms premiere. Paul Vaughan follows the tune's trail: how the words of Land of Hope and Glory were set to it. and how it became the country's second national anthem during the First World War. Repeated from Tuesday