A factory in China has denied using forced prison labour to produce Tesco charity Christmas cards after a little girl found a message from inmates inside a card.
Zhejiang Yunguang Printing told China's state-run Global Time: "We have never done such a thing."
It suggested the allegations were "manufactured" and may be politically motivated to smear China's human rights record.
The company was named by Tesco as the source of its charity Christmas cards after Florence Widdicombe, six, discovered a note in a card she was writing to friends.
In block capitals, it said: "We are foreign prisoners in Shanghai Qingpu prison China. Forced to work against our will.
"Please help us and notify human rights organisation. Use the link to contact Mr Peter Humphrey."
Former journalist and corporate investigator Mr Humphrey spent two years in the same prison and was notified of the message by Florence's father, Ben Widdicombe.
Tesco announced on Sunday it had suspended production at Zhejiang Yunguang Printing as part of its investigation into the message.
But the factory said the supermarket giant had not been in touch with it and only learned of its alleged involvement through the media.
"We only became aware of this when some foreign media contacted us. We have never done such a thing," Zhejiang Yunguang Printing told the nationalist newspaper.
"Why did they include our company's name? Do they have any evidence that we have been working with any prison?
"We have never had any connection with any prison.
"Are they trying to stir up a political thing? Are they trying to challenge our country's human rights?"
Chinese foreign ministry spokesman, Geng Shuang, said the allegation was "a farce" created by Mr Humphrey.
"Shanghai's Qingpu prison has no such foreign prisoners undergoing forced labour," he said on Monday.
Florence, whose family lives in Tooting, south London, told Sky News she thought the message was a prank.
"I was sitting down at the table writing my cards to my friends when I opened one and started laughing because someone had already written in the card.
"Then I passed it on to my mum. It took an hour to get our heads round it because we thought it was a prank."
After Florence's father got in touch with Mr Humphrey, he contacted some former prisoners who were in the foreign prisoner unit at Qingpu with him.
Writing in the Sunday Times, he said they confirmed inmates in the unit "are being forced into mundane manual assembly or packaging tasks" - including packing Christmas cards and gift tags for Tesco for at least the past two years.
Mr Humphrey said prisoners also make packaging and tags for Western clothing and that he had seen the names of other high street brands on the tags when he was in the prison.
A Tesco spokesman told Sky News: "We would never allow prison labour in our supply chain.
"We were shocked by these allegations and immediately halted production at the factory where these cards are produced and launched an investigation.
"We have a comprehensive auditing system in place and this supplier was independently audited as recently as last month and no evidence was found to suggest they had broken our rule banning the use of prison labour.
"If evidence is found we will permanently de-list the supplier."
Tesco donates Â£300,000 a year to the British Heart Foundation, Cancer Research UK and Diabetes UK from the sales of the cards.