Kate Middleton opts for a gown with a very daring neckline at the Palace banquet

She has drawn criticism for playing it safe in the fashion stakes, but tonight the Duchess of Cambridge proved she is not afraid of pushing the boundaries as she attended a glittering state banquet held in honour of the King and Queen of Spain.

Kate, 35, looked sensational in a dusty pink custom-made Marchesa gown as she joined Prince William, the Queen, the Duke of Edinburgh and other senior royals to welcome King Felipe VI and his wife Queen Letizia to Buckingham Palace.

The breathtaking floor-length dress featured a plunging V-neck in scalloped lace, which was a surprisingly revealing choice for the duchess and a departure from the conservative cuts she usually favours.

Kate drew further attention to her decolletage with an eye-catching diamond and ruby drop necklace, the ruby boucheron bandeau, which once belonged to the Queen Mother. The jewels fell just inches above the lowest point of the V-neck.

The garment's sheer bell sleeves added to its drama, which was offset by its soft colour and delicate lace fabric.

In keeping with royal tradition, Kate donned a tiara for the state dinner. The diamond and pearl Cambridge Lover's Knot tiara, which she wore to her first state banquet last year, was a piece beloved by William's late mother, Diana, Princess of Wales.

Kate finished the look with a favourite pair of diamond and pearl drop earrings.

The gown is markedly more daring than the dresses Kate chose to wear to her last two evening events, which both took place in March this year.

For an event at the Ambassador's residence she dazzled in an ice-blue Jenny Packham dress. While it caught the light with the beaded detailing, the sheer overlay meant very little skin was on show. 

Later in the month Kate stepped out for a fundraising event at the National Portrait Gallery in London in a glamorous forest green floor length gown by Temperley London, one of her favourite designers.

However while once again it was an elegant choice for the duchess, the long sleeves and high neck meant it was anything but risque.  

It might be that Kate wanted to step up the style stakes tonight as she was coming face to face with Queen Letizia, whom she is regularly pitted against on best dressed lists.