"This was the worst piece of unethical PR work I've seen," Francis Ingham, director-general of the UK's Public Relations and Communications Association, told BizNews. "It was just beyond the pale."
The influential industry body this week expelled Bell Pottinger from its ranks over the scandal, which has led to the resignation of senior management and an exodus of major clients, including Bunnings.
Bell Pottinger was Wesfarmers' UK PR agency and worked on the Bunnings UK and Ireland launch earlier this year, but a spokeswoman confirmed to news.com.au overnight the hardware giant had severed ties with the company.
Lord Timothy Bell, who resigned in August last year citing concerns about the South African account, told the BBC this week that it was "almost certainly curtains" for the company he founded in 1998.
The phrase "white monopoly capital" is popular among supporters of President Zuma, who accuse the minority white population of economically disadvantaging black South Africans.
President Zuma, who has been accused of stoking racial tensions and inciting violence against whites, earlier this year called for confiscation of white-owned land without compensation.
The goal of the campaign, according to leaked emails, was to encourage online activists to tweet and post about "economic apartheid", with Bell Pottinger tasked with creating material to "illustrate the apartheid that still exists".
Bell Pottinger had previously been involved in a sustained online propaganda campaign to "clean up" the image of the Guptas, including by editing the family's Wikipedia page.
Law firm Herbert Smith Freehills, which carried out a review of the Oakbay Capital account, said in its report this week that while the PR firm did not invent the term "white monopoly capital", it was used "on occasion by the Bell Pottinger account team as part of the economic emancipation campaign".
"Certain material that we have seen that was created for the campaign was negative or targeted towards wealthy white South African individuals or corporates and/or was potentially racially divisive and/or potentially offensive and was created in breach of relevant ethical principles," the report said.
But the law firm denied Bell Pottinger was behind the social media campaign.
"We have not seen any evidence to suggest that, as has been alleged, the Bell Pottinger account team used or instructed others to use so-called Twitterbots in the promotion of the economic emancipation campaign," it said.
Ingham said the work was clearly in breach of the PRCA's charter.
"Our charter says that members have to have the highest standards. Bell Pottinger didn't," he said.
"It says that members have to have the regard for the public interest, and Bell Pottinger clearly didn't and it says that members can't go around inciting racial hatred, which in our view, Bell Pottinger clearly did."
Bell Pottinger said in a statement that it acknowledged the PRCA's ruling, "accepts that there are lessons to be learned but disputes the basis on which the ruling was made".
"The overwhelming majority of our partners and employees played no part in the Oakbay Capital account and have not been accused of breaching the PRCA code," the statement said.
"Many of them will now consider applying for individual membership."
Bell Pottinger chief executive James Henderson resigned earlier this week, saying while he "neither initiated nor was involved in the Oakbay work" he accepted ultimate responsibility.
"I feel deeply let down by the colleagues who misled me," he told the BBC.
"However, I think it is important I take proper accountability for what has happened."
Phumzile Van Damme, spokeswoman for the opposition Democratic Alliance Party, which filed a complaint with the PRCA over the campaign earlier this year, welcomed the expulsion.
"Bell Pottinger exploited racial tensions in South Africa on behalf of the Gupta family, and Duduzane Zuma, President Jacob Zuma's son," she said.
"It will take our country years to rebuild our severely fragile race relations, which Bell Pottinger, the Guptas and the Zumas sought to exploit for their own financial gains."
The Democratic Alliance previously raised concerns about contents of a leaked Gupta email in which a senior adviser at Bell Pottinger identified "key moments" in a speech delivered by ANC Youth League leader Collins Maine.
"These key moments include the following quote: 'Those who want to disrupt the State of the Nation speech must prepare themselves for a civil war'," Van Damme said.
"It is disturbing that the incitement of a civil war in South Africa is identified as a 'key moment' by a Bell Pottinger adviser."
Earlier this week, Bell Pottinger's largest external shareholder, Chime Communications, handed back its 27 per cent stake for nothing in an attempt to distance itself from the company, The Times reported.
Bell Pottinger was most recently valued at £20 million ($36m) in 2012 when the management team bought three quarters of the company from Chime.
