A discount London book store has sparked social media controversy over the implications of a sticker placed on a book about the disappearance on Madeleine McCann.

Users reacted after customer Helen Rice noticed a label on a copy of Madeleine McCann - Ten Years On, that read "when it's gone, it's gone".

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After Rice uploaded a picture on Twitter, the post went viral, given that the police search for McCann, who was three at the time of her disappearance during a family holiday in Praia da Luz, Portugal, is still ongoing.

Speaking of the incident, Rice told The Mirror of her shock: "It was in the Clacton Common Factory Outlet branch in Clacton-on-Sea, Essex.

"I only popped up there for a walk and something to do after work yesterday afternoon, then had to check what I was seeing about three times."

Reaction on social media has been mixed, with many expressing anger.

"Do people not realise this is someone's child," asked one user, while another argued it was "so cruel to call a missing child 'it'". A further reply lambasted "the insensitivity of it all".

Other users suggested the shop had made an unintentional oversight: "This is ridiculous, It's just a slogan on a sticker, The Works was not at all trying to do this on purpose.. seriously," wrote Charlotte.

Reacting to the outrage, a spokesperson for The Works said: "We are truly sorry for any upset that this has caused and apologise unreservedly for the error."

Addressing concerns that the problem could have affected multiple copies of Danny Collins' book, the representative continued: "We believe this is an isolated occurrence but have taken immediate action to ensure that no other stores feature similar stickers on this book."

The incident comes after Madeleine's parents, Kate and Gerry McCann, spoke out on both the 10th anniversary of her disappearance on May 3, 2007, and her 14th birthday on May 12.

In a Facebook post paying tribute to their missing daughter, the Leicester-based couple, wrote: "Happy 14th Birthday, Madeleine! We love you and we're waiting for you and we're never going to give up".