1928. Radio broadcasting enabled the silence to be observed simultaneously across the country, and allowed millions of listeners to feel part of the ceremony. The BBC began broadcasting television pictures of the ceremony from 1937. The broadcast has run almost continually since its inception, interrupted only for the Second World War, making it one of the longest-running annual broadcasts in the world. Heritage status The Cenotaph was designated a grade I listed building on 5 February 1970. Listing provides legal protection from unauthorised demolition or modification. Grade I is the highest possible grade, reserved for buildings of "exceptional" historical or architectural interest and applied to 2.5 per cent of listings. The Cenotaph is in the care of English Heritage, which manages historic buildings for the nation. To mark the centenary of the First World War, Historic England conducted research into war memorials with the aim of listing 2,500. As part of the project, they identified 44 freestanding war memorials in England designed by Lutyens, which they declared to be a national collection. All 44 are listed buildings and had their list entries enhanced with new research; five (including Southampton) were upgraded to grade I on Remembrance Sunday 2014, joining the Cenotaph and the Arch of Remembrance in Leicester. Impact On Lutyens The renowned architectural historian Nikolaus Pevsner described the Cenotaph as "the chief national war memorial". Gavin Stamp, a British architectural historian and the author of Lutyens's entry in the Oxford Dictionary of National Biography, wrote that Lutyens's work commemorating the British war dead (the Cenotaph, his work with the IWGC and his memorial commissions elsewhere) was responsible for Lutyens's elevation to the status of a national figure. A few days after the unveiling, Lloyd George wrote to Lutyens: "the Cenotaph, by its very simplicity, fittingly expresses the memory in which the people hold all those who so bravely fought and died" in the war. In 1921, Lutyens was awarded the Royal Institute of British Architects' highest award, the Royal Gold Medal, for his body of work. Presenting the medal, the institute's president, John Simpson, described the Cenotaph as "the most remarkable of all [Lutyens's] creations [...] austere yet gracious, technically perfect, it is the very expression of repressed emotion, of massive simplicity of purpose, of the qualities which mark those whom it commemorates and those who raised it." According to Jane Brown, in her biography of the architect, Lutyens