Sally emerges back into the shop holding a pre-wrapped gift and finds her sister as she is now outside. As the camera pans away, the youngest version of her sister is seen in the shop window.

The shop-based scenes were filmed on a Sunday night in October, with film crews moving in as the final shoppers left and finishing up before 7am to maintain the secrecy around the advert.

Charlotte Lock, customer director for John Lewis, said: “Our shops are the beating heart of our brand and our customers love the ritual of Christmas shopping there – so we wanted to give the store a starring role in our ad for the first time.”

It is the second year that advertising company Saatchi & Saatchi, best known for the Thatcher-era “Labour Isn’t working” posters, has been responsible for the advert.

Franki Goodwin, chief creative officer at Saatchi & Saatchi, said: “We’ve all been there – time’s running out, and you’re still looking for the perfect gift for someone in your life who’s impossible to shop for. That’s why I believe viewers will truly connect with our heroine.”

The high street has continued to struggle as more shoppers move online. Footfall was down by 3.6 per cent in the year to October, and there have been more then 65,000 closures, according to consultants Altus Group, the majority of which were small, independent retailers.