Elizabeth II was never particularly enthusiastic about birthdays. They were a good excuse for a parade or an honours list, but not a patch on a major wedding anniversary, let alone a jubilee. Those were a celebration of true dedication, not of mere longevity. Even so, were she still with us, the late Queen would have acknowledged that her centenary on Tuesday is a big deal. It would also have created a delightful conundrum for the Buckingham Palace anniversaries office, the department that sends out 100th-birthday congratulations from the sovereign. At the start of her reign, she was sending 385 of those each year across all her realms (by telegram). By the end, it was over 16,000 (by card).

When her own mother reached 100 in the summer of 2000, the celebrations were tinged with disappointment. Having planned live coverage of the Queen Mother’s centenary pageant, the BBC scrapped the idea late in the day. Director-general Greg Dyke and his minions, then in thrall to Tony Blair’s ‘Cool Britannia’ vibe, thought it was all a bit passé and, besides, the timings would mean shunting Neighbours from its prime-time slot. So this exuberant assembly of all the Queen Mother’s favourite things, including VCs, Colditz veterans, the Poultry Club, Vera Lynn and the Wombles, was shelved in favour of the Aussie soap. Step forward ITV which saved the day, clocking up its best early-evening viewing figures in a decade. Cue a ferocious blame game at the BBC and a public apology from Dyke and his chairman. The Queen said nothing but pointedly knighted the pageant producer, Major Michael Parker, days later. Now, a new generation of executives has set about dismantling BBC Studios Events, the tiny unit behind every great state occasion you can think of (including the Cenotaph, royal weddings, funerals – and, yes, birthday parades). Its running costs are nugatory, yet its output is the essence of public service broadcasting. If the incoming DG wants to show he ‘gets’ the BBC, he will reverse this madness on day one. If not, it will take only one bungled veterans’ march-past before he hears the rattle of pitchforks.

Withering White House attacks on Downing Street; awkward questions about Britain’s armed forces; a monarch sent to Washington to patch things up. It’s 70 years since the Suez fiasco and the late Queen’s first US state visit. The Palace has been here before. Despite predictions that Donald Trump will somehow ‘embarrass’ the King and Queen during this month’s state visit, I think not. We met four months ago at Mar-a-Lago for my new book on Elizabeth II. He had only warm words for the late Queen and her eldest son – ‘a fighter’ – while refusing to be drawn on the difficult dukes. On his official visits to the UK, he has been a model guest. He will be the same as a host.

How, then, do we square Mr Trump’s rosy view of our head of state with his rambling contempt for our Prime Minister? I think it’s because he puts politicians in one box and 250 years of US/UK history in another. His predecessor, Joe Biden, always liked to proclaim his Irish heritage. Mr Trump is half-British. Read his speech at last year’s Windsor state banquet, and it’s hard to imagine any contemporary British politician being quite as effusive about this ‘lionhearted people’ who ‘defeated Napoleon, unleashed the Industrial Revolution, destroyed slavery and defended civilisation’. Mr Trump was thrilled to have two state visits. Mr Biden had none. I’m told that discreet soundings were taken to see if he’d like one. Back came a discreet ‘no thanks’.

Will there be dancing at Mr Trump’s state banquet? It used to be the White House norm. During the USA’s bicentenary in 1976, President Ford invited the Queen to join him for the first dance and was appalled when the band chose that moment to strike up ‘That’s Why The Lady Is A Tramp’ (she found it hilarious). In the Reagan years, the late Princess of Wales strutted her stuff across the White House floor with John Travolta. Then banquets became more business like and the dancing stopped. Mr Trump, however, loves his music. During my weekend at Mar-a-Lago, he hosted a pop concert on the lawn, a homage to the 1970s and 1980s. On the packed club terrace, he became DJ and summoned up many of his favourites – from Phantom of the Opera to Elvis and a spot of opera. ‘Isn’t this just the best high note?’ he whispered to me as Pavarotti reached the crescendo of ‘Nessun Dorma’ – the theme to the 1990 football World Cup. Mr Trump is co-hosting the next one this summer. Time for a posthumous encore from Luciano?