Amazon quickly pulled a line of products from a third-party seller bearing the slogans "Slavery gets shit done" and "Slavery makes shit happen," after the retailer was criticized by shoppers and advocacy groups for trivializing slavery - a practice which continues to this day especially in nations "liberated" by the US.

.@amazon how lovely is this? A little white boy with a highly insensitive and ignorant ‘Slavery Gets Shit Done’ bib on. Hmm.. did they pick the cotton right amazon? Or no? Gotta love 2018, what a great start. #Amazon #BOYCOTTAMAZON pic.twitter.com/DKKLFH4JKJ — Grace Croft (@Queen___Grace) January 19, 2018

Charities Anti-Slavery International (ASI) and International Justice Mission (IJM) UK lodged formal complaints over the line of T-shirts, mugs, baby bibs, tote bags and other items carried by the Marketplace seller.

"Children the same age as those modelling the T-shirts will be forced to work long hours for no pay in desperate conditions where starvation, beatings and sleep deprivation are common," said David Westlake, chief executive of IJM UK.

Absolutely shocking t-shirts! - "Amazon under fire for selling 'Slavery makes sh*t happen' t-shirts for kids". Come on @amazon, you should do better to control what you sell

https://t.co/BkJc8fNdFG — Anti-Slavery International (@Anti_Slavery) January 22, 2018

"If it is meant to be funny, it fails miserably," Jakub Sobik of Anti-Slavery International told the Thomson Reuters Foundation.

A spokesman for Anti Slavery International told MailOnline:

"I understand this is meant to be a joke, but slavery is no joke for the 40 million people who are experiencing it right now, including here in Britain. Slavery includes girls trafficked into prostitution or boys forced to work in sweatshops. They may be 'getting sh*t done' but I don't think they would find the t-shirt particularly funny."

There are an estimated 21 - 46 million slaves around the world today, subject to forced labor, sexual exploitation and domestic servitude. India has the highest actual number of slaves at an estimated 18.3 million people, however North Korea topping the list on a per-capita basis.

A spokesman for Amazon said: "All Marketplace sellers must follow our selling guidelines and those who don't will be subject to action including potential removal of their account," adding "The products in question are no longer available."