According to The Daily Telegraph, the dress came top in an online poll to find the 10 most iconic dresses of the last 50 years, beating other memorable garments such as Marilyn Monroe's white 'Seven Year Itch' halterneck and the wedding dress of Princess Diana. In 2016, the dress was voted the "Most Inspiring British Fashion Moment" in an online poll conducted by British online retailer Very.
In 2010, the performance in the Union Jack dress won Most Memorable Performance of 30 Years at the Brit Awards. The dress held the Guinness World Record for the most expensive piece of popstar clothing dealt at auction when it was sold for £41,320 in 1998.
At the 1997 BRIT Awards the Spice Girls were scheduled to perform, as well as being nominated for five awards, two of which they won. The black Gucci mini dress which Halliwell was given to perform in concerned her, as she thought it was too "boring". Then Halliwell decided she wanted to "celebrate being British", so she asked her sister to stitch on a Union Jack tea towel to the front as a patriotic gesture. After Karen, her sister, had sewn on the tea towel, Geri decided to wear it whilst performing "Who Do You Think You Are" (with excerpts of "Wannabe" in) at the BRIT Awards on 24 February 1997.
In 1998, a year after Halliwell performed in the dress, she auctioned it off at the London branch of Sotheby's for £41,320. The buyer was Peter Morton, on behalf of the Hard Rock Hotel and Casino, Las Vegas, who displayed the piece of clothing as pop memorabilia. Morton bid via telephone, and beat other bidders such as The Sun. Halliwell herself watched the "frenzied bid", and rapped the gavel after the final bid. The dress was originally valued at £12,000, but eventually it netted £36,200 (which, with the 15% commission, totalled it to £41,320). Halliwell gave the proceeds of the dress sale to a children's cancer care charity. The BBC commented on the sale, saying it "marks the end of Geri's links with the Girl Power image of the past". It holds the Guinness World Record for the most expensive piece of popstar clothing dealt at auction. The dress was one of many items of Spice Girls memorabilia sold at the auction, where total sales reached £146,511 for charity. The 1998 auction, with Halliwell auctioning off the Union Jack dress as the final lot, can be seen in the documentary Geri, by documentary film-maker Molly Dineen.
For the 2007 Spice Girls reunion tour, named the Return of the Spice Girls, fashion designer Roberto Cavalli designed Halliwell a new Union Jack dress modelled on the original. The new version appeared slightly longer and the flag was made out of rhinestones and Swarovski crystals. It was reported by various media outlets that Halliwell had attempted to buy back the original dress prior to the commencement of their world tour.