Princesses Margaret and Elizabeth give their minders the slip in this bubbly, giddily nostalgic royal romcom

If Enid Blyton had written a sequel to The King’s Speech, it might not have been all that unlike A Royal Night Out. Think of this fizzy and froth-topped comedy drama, about the young Princess Elizabeth and Margaret’s apocryphal adventures beyond the Buckingham Palace walls on the evening of May 8, 1945, as Two Go Mad On V.E. Day – which prepares you for its wryness and nostalgic sense of fun.

But it also allows space for you to be pleasantly surprised by the sharpness with which it observes a certain way of British life – and a certain style of monarchy with it – giving way, as it had to, to the next. 

Elizabeth is played by the Canadian actress Sarah Gadon, whose earlier work with David Cronenberg, in Maps to the Stars, Cosmopolis and A Dangerous Method might not have immediately convinced you she was the right person to portray our future Queen. 

But what Cronenberg sees in her, and what this film’s director, Julian Jarrold (Becoming Jane, Kinky Boots) also smartly draws out, is her talent for showing composure under pressure – and as the storm of the night whips up around her, she becomes its totally compelling eye. 

The chaos starts when boy-crazy Margaret (a very funny Bel Powley, making the same joke work a number ways) gives her officer minders the slip during the drab society ball they’ve been given reluctant dispensation by King George VI (Rupert Everett) and Queen Elizabeth (Emily Watson) to attend. 

Elizabeth chases her across London via Trafalgar Square, the fashionable Curzon nightclub in Mayfair and, later, 'Lord Stan’s’, a Soho establishment whose repute isn’t so much ill as croaking for mercy on its deathbed.

What the princesses come up against would be more rightly described as scrapes than drama, and Elizabeth has Jack Hodges (Jack Reynor), a working-class, republican soldier to chaperone her through the worst of it. But through her encounters with bereaved mothers and broken buildings, we see the seeds of a new kind of relationship between monarch and subjects, built on affinity and mutual respect, tentatively putting down root.

Writers Trevor De Silva and Kevin Hood devise a clever scene in which Elizabeth stands at the gates of Buckingham Palace on the same side as the crowd, looking up at her father waving awkwardly from the balcony, and there’s a moment, subtly and beautifully communicated by Gadon, when she realises this dynamic will no longer do.

Of course it’s lightweight, bordering on disposable. Any film in which the future Queen gets to chirp, in a cut-glass accent, “My sister has gone to Chelsea Barracks with a carload of tarts”, while the soundtrack cranks out American Patrol for what feels like the 10th time, could hardly be anything else.

And its historical connection to The King’s Speech is, I think, a little ham-fistedly flagged up. (It’s not that Everett is trying too hard to channel Colin Firth – in fact, he seems to owe more of his performance to a close study of Prince Charles – but the staging of certain scenes is overly familiar.)

But it’s also genuinely warm-spirited, with three lovable central performances from Gadon, Powley and Reynor. The film’s release has been very obviously timed to coincide with the V.E. Day 70th anniversary, and the recent happy arrival of Princess Charlotte can only help its boxoffice prospects. But it stands up on its own two high-heeled and champagne-giddy feet.