Pravin Gordhan is a conspiracy theorist who failed as a minister, President Jacob Zuma’s son Duduzane has purportedly said in an open letter.

“Mr Gordhan, you were Finance Minister of this country for over six of the last eight years, yet take no responsibility for this country’s economic performance in that time. It is always somebody else’s fault,” he writes.

Duduzane Zuma could not immediately be reached for comment.

Gordhan told the media that he would comment once he had read the letter and had consulted his lawyers.

Duduzane claimed in the open letter that, during Gordhan’s tenure at Treasury, the economy flatlined, unemployment rose from 21% to 27%, and the national debt increased from 31% to a record 51% of the GDP.

He said that Gordhan had used state bodies, such as the Financial Intelligence Centre and the SA Reserve Bank, to try and destroy him and his business colleagues, with no proof of misconduct.

“Yet you accuse us of state capture.”

The president’s son has numerous business interests which have direct and indirect links to the controversial Gupta family.

The leaked Gupta emails show that Duduzane Zuma was at the helm of a media spin machine, together with Bell Pottinger partner Victoria Geoghegan, to build a “long-term partnership” to “turn the tide of the country’s trajectory”.

In an email from Geoghegan to Duduzane Zuma – dated January 20, 2016 – she unpacks the £100 000 a month strategy to establish a “vehicle (the entity) to be the public face of the narrative to counter the public and media criticism [of the ruling party]”.

They also showed that Duduzane Zuma had bought an apartment worth nearly R18m at the Burj Khalifa skyscraper in Dubai, with assistance from the Guptas.

It was also established that a firm, that was partially owned by him, obtained shares in the Gupta’s Tegata company weeks before it bought Glencore’s Optimum coal complex in South Africa.

In his open letter, Duduzane Zuma says nothing about allegations of corruption involving the Guptas. He claims that former Public Protector Thuli Madonsela’s “State of Capture” report was inconclusive and that the Hawks had found no wrongdoing involving him.

“You are a conspiracy theorist who failed as a minister of this great country. You grandstand in Parliament and embarrass this country. Do you not think that the people of this country can see what you are doing?

“People are innocent until proven guilty. I challenge you, take me to court if you think you have a case.”

Madonsela investigated allegations that the Guptas offered government officials, including ANC MP Vytjie Mentor, Cabinet posts in exchange for government tenders and other favours.

Zuma allegedly allowed his son Duduzane and the Guptas to be involved in appointing board members of state-owned enterprises, and to be involved in former finance minister Nhlanhla Nene’s removal in December 2015.

Last year, then-deputy finance minister Mcebisi Jonas stated that the Guptas had offered him R600 000 in cash, as well as a promise of R600m, to take over as minister. Jonas said he had refused the offer.

In March this year, President Zuma axed Gordhan and Jonas in a controversial Cabinet reshuffle.

The open letter states that both Zuma and the Guptas had consistently welcomed a judicial commission of inquiry into state capture. They had pledged 15 months ago to exit their South African investments to protect jobs.

“How do you sleep at night? Does putting over 7 500 South Africans out of work even bother you?”

He accused Gordhan of protecting big business.

“The youth of this country that is desperate for hope and a chance to succeed, will eventually see you exposed for what you are. I am selling my shares to be able to focus my time on clearing my name.”

He warned Gordhan against making further public statements which could affect his reputation.

On Friday, Duduzane’s outspoken brother Edward heckled Gordhan during the Gandhi Memorial Lecture.

Gordhan said at the event that the country was not for sale. He was reportedly supported by a large segment of the crowd during the fracas.