On May 8th 1945, as Victory in Europe is declared, London's streets fill with revellers. In Buckingham Palace, teen princesses Elizabeth and Margaret (Gadon and Powley) are aching to join the merrymaking after being locked away during the war. Their mother the Queen (Watson) disapproves, but the King (Everett) lets them go, accompanied by two guards (Laskey and Gordon). During the lively celebrations at The Ritz, they escape their chaperones and have a night on the town, as Elizabeth teams up with airman Jack (Reynor) to track down the flighty Margaret.

Director Jarrold does a remarkable job recreating the jubilation that night. Viewers from subsequent generations won't have any idea how it feels to celebrate victory like this, as wars since them haven't ended on a remotely triumphant note. So watching the streets and squares overrun with flag-waving Brits is unexpectedly resonant. The scale of this is beautifully recreated, as is a realistic sense of London's geography and history, from a Mayfair club to a Soho drug den to a boat ride on the Thames.

Gadon and Powley nicely heighten their roles: Margaret is a bubbly, giggly airhead (the film sidesteps the fact that she was 14), while Elizabeth has a sobering sense of her future role. Both are terrific film characters, likeable and easy to sympathise with. It's also easy to believe that no one recognises them int he street, something impossible to imagine today. They're strongly supported by the dashing Reynor and the textured double-act of Everett and Watson, plus terrific side roles for Allam (as a helpful gangster) and Sheen (as Jack's mum).

This is such an effervescent romp that it's almost impossible not to love it. Even as it tips over into silly slapstick from time to time, or glosses over the darker elements, the film is strikingly written, directed and played to be both entertaining and imaginative in the way it creates scenes that just might have happened, but probably didn't. So even if it ultimately feels weightless and silly, there's enough intelligent subtext to hold our interest.

themes, some violence, innuendo

7.May.15