Caitlyn Jenner poses with Cuppa charity merchandise
Prime Minister Boris Johnson’s father Stanley, who also appeared in the show, apparently expressed an interest when his booking agency was approached.
But he withdrew when his PR team discovered the charity was not registered.
Mr Johnson said that payment was never discussed.
Reporters from Channel 4’s Dispatches programme created a hoax charity called Cleaning Up Plastic Pollution in Africa (CUPPA), with a website and merchandise, after a tip-off that high-profile celebrities were charging charities huge sums of money for their support.
After contacting celebrity booking agents, investigators were told that former football manager Redknapp, 73, would be willing to back the charity.
But it would cost £15,000 for him to do a post on Instagram and an extra £5,000 for a photoshoot.
Reporters signed a contract, paid the agency £20,000 and secretly filmed the session.
A week later, a photograph of Redknapp wearing a CUPPA T-shirt and cap, and holding a themed cup, was posted on his Instagram page without disclosing that he was paid for the post.
Stanley Johnson said payment was never discussed
He wrote: “I’m proud to support CUPPA – a great new charity that’s Clearing Up Plastic Pollution in Africa. Follow them on Insta to show your support.”
A lawyer for Redknapp said that he was a “prolific” supporter of charities, had never received fees and “would never knowingly charge for the regular charity work he undertakes”.
The representative added: “In this case he only agreed to payment after being informed that the charity was supported by private investors. He was paid less than the sum quoted by MN2S [the talent agency].”
Investigators paid MN2S more than £19,500 for former Olympic decathlete Jenner to take part in a photoshoot and share an Insta-gram post.
In a video filmed on a phone, Jenner, 70, speaks about why she is backing the charity.
She says: “I think we have to be good stewards of this planet. And the plastic issue is huge. It’s not easy to do but it can be done.
“Clean the beaches up, clean areas up, especially plastics because they don’t go away.
“We need to be good stewards and it is something we can fix.”
Harry Redknapp was described as a ‘prolific’ supporter of charities
Jenner posted a photograph of herself wearing a CUPPA T-shirt and holding a cup on her Instagram the next day, but did not make clear she was paid. A lawyer for Jenner said: “Apart from this instance, she has never been paid for her charitable work.
“She always intended to donate the money raised via the photoshoot and Instagram post to charities she supports.
“She feels that she has been targeted in the programme because of her status as a well-known TV personality and that she has been exploited to increase viewing figures.”
Posing as CUPPA, Dispatches also contacted talent booking agency Champions plc, which said Stanley Johnson’s fee to be a charity ambassador or attend an event would be £30,000 to £40,000.
A celebrity manager told an undercover reporter “he’s basically getting it passed by the Prime Minister’s office”, before sending an email saying Johnson’s PR team said they could not allow him to because “they can’t see it as a registered charity”.
Johnson, 79, insisted that payment was never discussed with him and, had it been, he would not have accepted.
A representative for MN2S said that it agreed fees for its celebrity clients to do one-off fundraising work, adding: “In those instances, we may agree a fee that covers not just the individual but the work of the team that make it possible.
“This is widely known within the charity sector. The fee is often heavily discounted from the commercial rate, as was the case with the celebrities we work with and CUPPA.”
A spokesman for Champions plc, said: “The vast majority of our charity engagements are carried out free of charge.
“Over the last three years, Champions has given more than 10 percent of its annual profits to charity.
“When approached undercover by Dispatches, we believed that the brief was to help raise the profile of an unknown charity that wished to engage celebrities to perform at a private launch event funded by private benefactors.
“It would be wrong to conclude that all those named would have been aware that they were even under discussion.
“Champions are a responsible organisation and will of course watch the programme carefully.
“Should it raise any concerns we will investigate and take action where appropriate.”
● Celebs For Sale: The Great Charity Scandal, Dispatches on Channel 4, tomorrow, 8pm.