The Diamond Queen, BBC1

Republicans beware: this is no time for controversy

Ever since Queengate, the BBC has been suffering from post-traumatic stress disorder when it comes to Her Majesty Elizabeth II. Senior executives only have to see her face on a postage stamp to be hit with sweaty flashbacks of what can happen (and how fast) when things go wrong with a royal documentary. That woman can end careers.

So it wasn't entirely surprising to find that there were to be no advance previews of The Diamond Queen, a three-part series about the monarch to mark her 60 years on the throne. "We want everyone to watch it at the same time," was the (unofficial) explanation I got, conjuring images of an awed nation gathered round a goldfish-bowl screen in loyal unity. No great surprise either to find that Andy Marr, the Corporation's safest pair of hands, had got the job of presenting this broadcast equivalent of a commemorative plate. Her Majesty would unquestionably be safe with him.

So there was no moment to compare with the Annie Leibovitz portrait "incident" that never was in the 2007 documentary A Year With The Queen, and nothing that will be requiring an apology this time. The interesting question though, for anyone with even a hint of scepticism about the burgeoning Jubilee cringe, was whether he was going to be safe with her. She has a way of making even the hardest brains go soft. Monarchy is a kind of kryptonite for journalism.

On last night's evidence the brain is still in there and working well enough to let him know he couldn't possibly show it – except in a nicely turned phrase here and there. "We've taken her rather for granted," he said at the beginning, "and after 60 years perhaps it's time we stopped." Retool that only slightly and you might have a republican battle cry, but Marr's trademark wryness as he delivered was tilted in the opposite direction. "She's very rich, privileged, protected and cherished," he said later, countering three adjectives that sounded as if they might be raising a question about her status with one that acknowledged there probably wasn't much point. And, more than once, he asked what she was for and what she actually did – bluntly utilitarian questions that never really got an answer. Instead there was the familiar swirl of talk about duty and experience, wisdom and "magic". And quite a bit of royal heirloom gawping – at the Queen's desk and the Queen's Wendy House, which Princess Beatrice and Marr squeezed into to exchange small talk about fabric patterns.

Douglas Hurd said the most subversive thing by far, commenting on the Queen's relationship with Margaret Thatcher: "They each thought the other was rather strange... which was true," he chuckled. But elsewhere everything was soft and satiny and gently ruffled – a prestige display case for a national treasure. Marr wore white gloves in the Royal Archives, as he examined the instrument of abdication (genuinely rapt as he pointed out "a signature which destroys itself") and he never really took them off for the rest of the programme. The Queen, you might have finally concluded, provides a unique service as a kind of therapist/confessor for troubled Prime Ministers (discretion guaranteed), or a "symbol of the country on legs", or as Marr himself finally summed up "our slightly mysterious Department of Friendliness". But you would have been very hard pressed to conclude that sane people might actually question her constitutional status. Which, I imagine, is exactly what the BBC asked for in the first place.