With the economy faltering and the Government hanging on by a thread, the Queen’s Silver Jubilee was an unmissable opportunity to instil some feel-good factor into 1977. However, an “anti-monarchist” at the Department of Energy was threatening to ruin plans for a floodlit spectacle in London.

Lord Drogheda, the chairman of the London Celebrations Committee of the Queen’s Silver Jubilee, had coordinated events that included a plan to light up the Thames. Although he did not name the culprit, it seems reasonable to suspect that the allegedly unenthusiastic minister was Tony Benn, the Secretary of State.

A letter that was written in June 1976 from the Home Office to Downing Street, outlining the problems with floodlighting, bears handwritten remarks from the Prime Minister that clearly show his view: “Bloody nonsense . . . I think this is pernickety bureaucracy.” The inter-departmental wrangling continued.

In December, Ken Stowe, the Principal Private Secretary, informed James Callaghan that Lord Drogheda had expressed “the belief that your direction about providing floodlighting for London buildings is being undermined by the ‘anti-Monarchist in DoE’.”

Mr Benn wrote in his diaries that the jubilee address to the Queen at Parliament “was another reminder of how totally undemocratic British democracy is” – and he was not the only one to be irritated by all of the fuss.

Callaghan was unimpressed with Westminster City Council’s plans for a son et lumière display in Horse Guards Parade, which backs on to Downing Street, during the summer. He wrote on a document that he did not want this to happen until Parliament rose for the summer: “I don’t mind August but I can’t take July which is always a bad month in parly terms.”

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