The royal wedding unveil its last screen at the moment we got the first through-the-car-window look at Kate’s slim lace sleeve, 1950s neckline, veil edged with scalloped chantilly and – to whoops of joy on the fashion desk – a glimpse of Sarah Burton herself helping the train into the car.

None ever doubted that Kate would go British, but her decision to work with the relatively unknown designer Sarah Burton at Alexander McQueen was a stroke of genius. There was, quite simply, no one better talented or more qualified for the job. Its delicate lace sleeves, stunning satin bodice and cleverly pleated skirt combine traditional fabrics with a contemporary silhouette, clearly inspired by the gown Hollywood beauty Grace Kelly wore when she married Prince Rainier of Monaco in 1956.

The dress symbolized what worked about this wedding. It was grand but romantic, traditional but unexpected. It dispatched all memories of Diana’s schlocky, overblown dress by zeroing in on a far more elegant, sophisticated version of the princess ideal in Grace Kelly. It combined notes of British with an international appeal.

The primary reference is Kelly’s marriage, but the shape also recalls the dress worn by Princess Margaret at her wedding four years later; the lace sleeves nod to the dresses of the Italian Catholic tradition, but the design of the lace itself – handmade at Hampton Court – features roses, thistles, daffodils and shamrock.

Crucially, the choice of Sarah Burton and the Alexander McQueen label is a hugely encouraging sign that Kate has a modern understanding of what it is that makes Britain great in the 21st century. Encouraging because – whether you like it or not – Kate and William will play as key a part of the image of Britain abroad in the next decade as the Harry Potter franchise has in the last.