Samantha Cameron does British fashion proud at White House dinner - in pictures

Samantha Cameron and Michelle Obama both did polite sartorial nationalism. Cult red carpet designer Alessandra Rich was Samcam's choice, whilst Mrs O also went for a blue gown. Hers was by the British born, but very much US based, label Marchesa. Footnote: Georgina Chapman who co-designs for the label is married to Harvey Weinstein - both were also guests Photograph: Rex Features/Rex Features

The First Ladies rocked a similar silhouette - albeit one with very different necklines. Did they talk about both wearing complimentary blue earlier? Photograph: Carolyn Kaster/AP

Michelle does NOT look impressed that POTUS is stepping on her gown. And nor would we be Photograph: Susan Walsh/AP

Harvey Weinstein with his wife, Marchesa designer Georgina Chapman. There's a blue-ish theme emerging, though Chapman's is more starry starry night Photograph: Charles Dharapak/AP

Anna Wintour judged Chanel Haute Couture the most White House-appropriate thing in her wardrobe. Meanwhile Shelby Bryan did a strict retro thing with his hair Photograph: Charles Dharapak/AP

British actor Helen McCrory ups the monochrome count - not sure about those gloves. Damaian Lewis can afford to look smug - the tux fits nicely and Homeland is apparently Obama's favourite TV show Photograph: Charles Dharapak/AP

Yeah yeah that's the VP Joe Biden with William Hague. Whatever. But Jill - whatcha wearing there? It's one part Biden does Baden-Baden, two parts Coast bridal in Mauritius Photograph: Susan Walsh/AP

On balance it's a good thing that Elizabeth Lee McGovern aka Cora Crawley, still looks a bit Downton for the White House. Photograph: Charles Dharapak/AP

Idris Elba's shoes are a tad too shiny if we're being critical (we are). But then, he's never looked as good as he did as Stringer Bell in the Wire season three Photograph: Charles Dharapak/AP

Hugh Bonneville and LuLu Williams walk the marble chequered catwalk. Excuse me Lord Grantham, but isn't your jacket pulling a little there? Photograph: Charles Dharapak/AP

US Secretary of Health and Human Services Kathleen Sebelius ups the blue ante for the night. It's the perfect compliment to her hair and both her accessories - the leopard scarf and her son Ned Sebelius - look fun Photograph: Benjamin Myers/Reuters

US Congressman John Dingell and his wife Deborah. The red's shouty, but unfortunately it's shouting "STAID, TRAD, and DULL" Photograph: Benjamin Myers/Reuters

Former New York City Mayor Ed Koch and Diane Mulcahy. Diane's picking up the Tilda Swinton baton here by doing the leftfield trouser thing. The monochrome's good but the shoes should have been less prissy, more Celine-ish to convince us Photograph: Charles Dharapak/AP