A graphite drawing by a little-known South African artist of Nelson Mandela as Jesus Christ at the Last Supper and signed by Mandela has apparently attracted a bid of $2,5-million (R16-million). But it's not just the signature or the controversial content of the drawing by Dean Simon that's raising eyebrows.

The almost inconceivable price tag attached to the artwork and the circumstances of the proposed sale don't seem to add up.

According to a statement by a publicist, Suzie Hozack, about the sale of the drawing, which was followed by a report in The Times newspaper last month, Mxolisi Mbetse, the chief executive of the Industrial Development Group, had formally offered $2,5-million to the anonymous owner of the artwork.

Sean O'Toole, an independent arts journalist and critic, said that if was true, the offer dwarfed the world record set this week for Irma Stern's Gladioli, sold to an unnamed buyer for R13,36-million at Straus & Company auctioneers in Cape Town.

It was the highest price paid for a South African painting on auction. But Swazi Tshabalala, Mbetse's personal assistant, said on Wednesday: "We have no idea where the hell that claim came from."

Mbetse's nephew, Thandana Mbetse, phoned the Mail & Guardian an hour later to say his uncle was on a business trip in Asia and could not be reached.

In reply to written questions sent to Thandana for his uncle, Thandana said: "I can — state categorically, having intimate knowledge of our family affairs, that Mr Mbetse knows nothing about the offer made for this painting [sic] and that the first time we were made aware of its existence was when we read about this alleged offer in the press.

"Mr Mbetse has no idea how his name became associated with the painting and he has no interest in pursuing this matter," he said.

But Hozack (who was quoted as Suzie Copperthwaite in the Times article but says she recently married), said that her client had "a written offer" from Mbetse for the work.

"Mbetse wasn't sensitive at the time [the Times article was published]. He agreed for those details to be released in the media because, without them, I didn't have a story to tell," she said.

She denied that the press report was a calculated leak to raise the price of the artwork ahead of a possible sale. "As far as I'm aware, that's not the case," Hozack said.

According to the statement from Hozack, one of 50 giclée (ink-jet) prints of the original -- each also signed by Mandela -- will be auctioned at a dinner on October 21, at the luxurious boutique Saxon Hotel in Sandhurst, Johannesburg, which would be "attended by high-profile guests".

The proceeds of the sale would be donated to the Nelson Mandela Children's Fund.

The prints had a minimum price tag of R500 000 each, Hozack said, but she did not know what would happen to the proceeds from the sale of the other 49 prints.

For his part, O'Toole poured scorn on the reported price tag of the prints: "R500 000? Good luck to them. Not even William Kentridge would be arrogant enough to expect to command such a fee."

Signed Mandela artworks have a controversial history.

In 20 05 Mandela sued his former lawyer and confidant, Ismail Ayob, and Ayob's business associate, Ross Calder, for the unauthorised reproduction and sale of watercolours and handprints which Ayob claimed had been hand-painted by Mandela.

The proceeds of the sale were supposed to flow to the Nelson Mandela Children's Fund, but millions of rands were unaccounted for.

This time, however, Mandela's signature on the original drawing of The Last Supper and the 50 prints was "not planned" and "out of my hands", said Simon, who was commissioned to do the work by Hozack's client in 20 06.

According to Simon, the work hung in the owner's home where it was admired by many, including Mandela's eldest granddaughter, Ndileka Mandela.

It was at that stage, Simon said, that the owner began to receive requests for copies, with offers of R500 000 for each of them.

Ndileka requested a copy of the original to show to her grandfather, which Simon, who retained the copyright, said he provided about 18 months ago at the request of the owner. Mandela signed both the copy and the original which the owner had taken with him.

"Mandela loved it," Simon said.

After that, Simon produced additional prints which Ndileka took to Mandela to sign in batches. Simon said he and the owner had a 50-50 agreement to split the sale of the prints.

The Nelson Mandela's Children's Fund did not respond to repeated requests to provide clarity about the drawing, the proposed donation, Mandela's signatures and Ndileka Mandela's involvement.