In an old granary building behind King's Cross Station, Paul Smith kept to his signature style with a collection of elegant matching suits in vivid colours ranging from clean white and bright blue to sunshine yellow.
Transparent silk voile shirts were unbuttoned low to reveal a sliver of skin and tucked into high-waisted, 1970s-style wide trousers or shorts, for an effortless spring/summer cool.
Blocks of colour were interspersed with traditional patterns, from a silk mix jacket with a checkered print to a blouse printed with daffodils matched with wide yellow trousers.
Earlier, designer Alice Temperley took her luxury line Temperley London up a notch with a fairytale collection of sweeping gowns in gentle pink, blush, lilac, mint and white.
There were long dresses embroidered with hand-cut silk flowers and with lace and crystals, gowns printed with a pattern of purple orchids and lace created out of the patterns of trailing leaves.
"It's about transporting you into another mood. We all live such normal lives, with work, it's nice to have fantasy clothes," the designer told AFP backstage after the show.
The label recently appointed a new chief executive, Ulrik Garde Due, who will use his experience at Burberry and Celine to promote it as a luxury lifestyle brand.
"Now we've got the (everyday) Alice line, we've got a good business, we don't have to be so commercial with the runway. We can be more creative," Temperley said.
At the other end of the market, fashion chain Topshop unveiled its latest Unique collection in a tent in Regent's Park, staging a "Heat Rave" filled with all the best bits of summer.
Under the gaze of chief executive Philip Green, model Kate Moss and US Vogue editor Anna Wintour, the models sported loose sun dresses, rucksacks packed for the beach and slip-on mules as they walked along the grass floor.
There were ethnic patterns and vibrant colours reflecting the blue of the sky and sea, while a V-necked white dress was adorned with mirrors to reflect the glittering of the sun.
Sunday also saw the latest collection from Mary Katrantzou, who took shoes as her inspiration for this season's take on the graphic prints that made her famous.
The leather detailing on a pair of brown brogues was magnified and printed onto a halterneck dress, while other outfits featured oversized zips and laces.
The Greek designer also played with shapes and texture with dresses that looked like full skirts pulled up under the arms, embellished with sequins, mirrors and crystals.