Tesco said it was absolutely appalled on the reports of the Christmas card: "We abhor the use of prison labor and would never allow it in our supply chain," a Tesco spokesman said on Sunday.

"We were shocked by these allegations and immediately suspended the factory where these cards are produced and launched an investigation," the spokesman said.

The note also said: "Use the link to contact Mr. Peter Humphrey." 

Peter Humphrey is a former investigative journalist that spent several years in a Chinese prison that forced prisoners to work 15-hour days manufacturing clothing. 

Humphrey said his wife Yu Yingzen and him were both sentenced to the Chinese jail in 2014 for obtaining illegal records on Chinese citizens. The couple spent about a year in jail and were eventually deported in 2015. 

Humphrey told Sky News that he believes the card came from the Zheijiang Yunguang Printing factory, where prisoners were used in the production line as slave laborers.