The small sachet tumbled out of the 20-year-old supermodel’s handbag and on to the floor as she searched for her keys.
Cara swiftly covered the packet with her foot, then her handbag before snatching it up.

She has become the biggest British model since her idol Kate Moss — and like her heroine has a reputation for hard-partying.
One friend said: “Cara’s the biggest name in fashion right now. But she’s also become a massive name on the party circuit — just like Kate.
“People are beginning to worry she’s overdoing it and that it could end up risking her health.”

Cara was pictured dropping the packet of powder, which looked like it could be cocaine, as she returned to her home in Belgravia, central London, on Wednesday afternoon following a meeting with designers.
Photographers who saw Cara arrive with a pal said she seemed “energetic” as she struggled to find her house keys. One said: “She was trying to get inside her house. She said, ‘I’ve lost my keys guys, I’ve lost my keys’.
“She was really giggly. She found it hilarious but her friend was really edgy about it. Suddenly Cara dropped something and bent over to pick it up.
“Very discreetly, she just put her foot on it and then rolled her handbag across so it looked like she was just kind of bending over.

“The friend kept saying, ‘Can you stop taking pictures?’ The friend definitely realised they were in trouble once that little packet had dropped on the ground.”
After failing to find the keys, bisexual Cara went to her model agency Storm for help. She later returned with two men in suits who let her into her house.

Cara had been partying the night before with her close showbiz pal Rita Ora.
The pair, who call each other “wifey”, watched Beyonce at the O2.
They then went on to a party at Soho nightclub Box, where the guests included Kate Moss and fashion designer Stella McCartney. At 2am Cara and Rita headed off to another party in Chelsea.
Cara has had a meteoric rise to fame since being signed by Storm in 2009.

She was spotted by talent scout Sarah Doukas, who also discovered Kate Moss.
Cara is the granddaughter of ex-English Heritage chairman Sir Jocelyn Stevens, founder of pirate station Radio Caroline.
She went to £30,000-a-year Bedales girls’ school and grew up in London with her property developer dad Charles and mum Pandora, a personal shopper.
Last year she won the Model of the Year award at the British Fashion Awards after starring in campaigns for Burberry, Chanel, Zara and H&M.
She appeared this month on the cover of the launch edition of the magazine Miss Vogue.
Her friends include singer Jessie J, Radio 1 host Nick Grimshaw, TV presenter Alexa Chung, Mick Jagger’s daughter Georgia May and fellow model Jourdan Dunn.
And in November she hung out with Rihanna as the singer visited London.
At the time, Cara said: “She’s calling me a rock star and I was like, ‘But you’re Rihanna. You’re amazing’.”
In 2005, Cara’s idol Kate was forced to apologise after photos of her allegedly taking cocaine were published.
The pictures are said to have cost her millions of pounds in cancelled contracts.
Cara’s agency Storm declined to comment yesterday.
Cara Delevingne New York