When the fourth series of Downton Abbey begins on Sunday night on ITV, the yellow Labrador’s tail wagging in time with the music that accompanies the opening credits (that dog has survived where others have fallen to war, Spanish flu, childbirth and car accidents), the year is 1922.

A year in which James Joyce’s Ulysses was first published, a year in which the Jazz Age began to blossom, a year in which ankles were an ‘extremely erotic zone’. 

Kerry Taylor, an auctioneer specialising in vintage fashion and textiles, explains:  ‘The dresses in 1922 were long and shapeless, people have come out of World War I and women have started doing proper jobs and need a bit of freedom, so clothes are easier to wear, the corsetry is gone. So you’re getting glimpses of ankle, which sends all the men into ecstasy. Ankles are an extremely erotic zone.’

Those Flapper-style dresses we think of when we think of the 1920s, she explains, came later in the decade and for now dresses – often in rich velvets or repeat pattern beading – fell far past the knee, in a sort of loose sack shape. ‘It’s like a uni-bosom that just goes on down,’ Taylor says, ‘the clothes are sort of baggy really, it’s a cylindrical look that you’re getting.’

"Those Flapper-style dresses we think of when we think of the 1920s came later in the decade and for now dresses fell far past the knee, in a sort of loose sack shape."

But while the silhouettes were almost frumpy, the colours were anything but. ‘Colours are very rich in 1922: jade greens; oranges;  very bright, happy colours; rose pinks; coming out of the war and the dourness and all the black of the widows,’  says Taylor. Of course Lady Mary will be in mourning throughout season four, Matthew Crawley having died on his way home from visiting their first-born in hospital, but her mourning attire will be less pronounced than it may have been before. Cally Blackman, a fashion historian who wrote 100 Years of Fashion (Laurence King), explains: ‘Mourning clothes, which had been a cult in the 19th century, was becoming less widely worn. The Great War and the 1918 Spanish flu epidemic wiped out millions of people, nearly everyone suffered the loss of a family member, so adhering to complex mourning regulations became almost impossible. But black was becoming a fashionable colour in its own right…’

Married women and single women wore the same styles of dress, but married women were more likely to wear a hat. ‘There was still that hangover from the Edwardian period,’ says Taylor, ‘it was de rigueur for a married woman to wear a hat, whereas an unmarried lady wouldn’t be required to wear a hat.’ Many chose to, however, and Blackman notes that the ‘head-hugging cloche was the hat of choice’, a style we expect to see frequently on the impish and mischievous Lady Rose. 

Hair decorations were also extremely popular and this was an era in which there were great developments being made in industrial processes. Susan Caplan, an expert in vintage jewellery, says, ‘Tortoiseshell and celluloid combs were seen throughout society thanks to the advancement of plastic processes that could be used to manipulate materials such as Bakelite. And of course flappers were fans of the headband and feathers and crystal – or diamonds for high society members – embellished hair ornaments.’  Generally, a lot of the jewellery reflected that almost languid shape of the clothes with drop earrings prevalent and necklaces, in pearl or onyx, hanging long.  

"The British aristocracy, women like the Crawleys, would have travelled to Paris once or twice a year to buy clothes."

Handbags were discreet, ‘just large enough to fit the new powder compacts, a lipstick and a handkerchief', says Blackman, ‘but it was still not considered ladylike to wear too much make-up’. ‘Yes, bags tended to be small,’ adds Taylor, ‘all you had to do was hold a pound note and that would keep you going all week.’

Cultural and political developments had an impact on fashion too, and after Tutankhamen’s tomb was discovered in 1922, Egyptian influences began to be seen. ‘The whole world goes Egyptian-mad after that,’ Taylor explains, ‘so you get hieroglyphics on jackets, you get little beaded Pharaohs, you get big papyrus flowers as motifs on the 1920s dresses.’ The Bolshevik revolution also impacted fashion and as Russian émigrés, aristocrats and artists, fled to Paris, more Russian shapes and details began to be seen in the clothes coming from France.

"Women voted and worked now ... by the end of the 1920s you might have even spotted a woman wearing a pair of trousers."

The British aristocracy, women like the Crawleys, would have travelled to Paris once or twice a year to buy clothes. Yes, there were seamstress and dressmakers nearby, and in London they would have shopped at Selfridges or Debenhams (then Debenham & Freebody) but when they required something very special they would go Paris – on the Blue Train or by plane as by the early 1920s, it was possible to fly from Croydon airport to Paris via Le Bourget in two and a half hours – for couture.

They would have called to the boutiques of Jeanne Lanvin, Paul Poiret and, of course, Coco Chanel, who was to revolutionise women’s wardrobes in the coming years. Hemlines were about to rise above that erogenous ankle, those baggy shapeless shifts were going to become more slinky and streamlined, and by the end of the 1920s you might have even spotted a woman wearing a pair of trousers. Goodness knows what the dowager would have to say about that.