Evidence from witnesses and previously unpublished documents raise the question of whether Banks was trying to bribe the police chief in a bid to discredit Chris Kimber.
The millionaire who bankrolled Brexit discussed lucrative business opportunities with one of South Africa’s most senior policemen while trying to persuade officers to investigate a former business partner.
A Channel 4 News investigation can reveal that Arron Banks fostered a close relationship with the top cop while South African police were considering launching a criminal investigation into business rival Chris Kimber.
Evidence from witnesses and previously unpublished documents raise the question of whether Banks was trying to bribe the police chief in a bid to discredit Mr Kimber, his former partner in a number of South African diamond mines.
Mr Kimber has claimed that Mr Banks had travelled to Russia to raise cash for his mines, and that money he raised from investors was spent on the Brexit campaign.
Arron Banks became Britain’s biggest political donor after giving £8 million to Brexit causes, but is now subject to an investigation by the National Crime Agency into the source of the funds.
He has previously denied bribing a public official and that Russia was the source of any of his political donations.
Any offer or payment to a public official to persuade them to act in a certain way could constitute an offence under the UK Bribery Act 2010, with a potential 10-year jail term.
Though best known in Britain for his insurance businesses, Mr Banks holds interests in several diamond mines in South Africa and neighbouring Lesotho.
In 2013 he went into business with Chris Kimber. The two planned to share and operate diamond mines in Kimberley.
But the partners fell out and they became embroiled in a string of bitter legal disputes.
Channel 4 News has previously revealed how Mr Kimber alleged in court papers that Mr Banks travelled to Russia to try to attract investment in his diamond businesses.
Mr Kimber said his ex-partner promised to pump money from investors into their mining venture, but spent the money on the Brexit campaign instead.
Now new evidence has emerged raising the question of whether Mr Banks tried to bribe police to launch a major investigation into Mr Kimber in a bid to discredit him or even put him behind bars.
A former senior police officer, General Johan Booysen, said he agreed to introduce Mr Banks to General Kholekile Derek “KD” Galawe in a Pretoria hotel in May 2017.
General Galawe is the Head of the Directorate of Priority Crime Investigations, known as the Hawks, in the Northern Cape Province, where Mr Banks owns a number of mines.
General Booysen said: “The long and short of story is that according to him [Mr Banks], Kimber had done him in, and he wanted Kimber to be investigated.
“I explained to him that I’d left the police and the Hawks and that what I can do for him is introduce him to the head of the Hawks in the Northern Cape, General Galawe, which I indeed did.
“Galawe incidentally happened to be in Pretoria at the same time and he came over to the hotel. I introduced him and my understanding is that Galawe was then going to take this investigation forward.”
Evidence from witnesses and documents show that Mr Banks went on to discuss a series of potentially lucrative investment opportunities with General Galawe at the same time that Mr Banks’s complaint was being considered.
The general’s business adviser JJ Njeke told Channel 4 News: “At some stage he had been talking to Mr Banks about buying an interest in his call centre business in South Africa.
“Also assisting him in other business ventures, including an interest in cement and things like that. But I don’t know if they ultimately made any investments together.”
General Galawe admitted he toured Mr Banks’s Outworx call centre in Durban with Mr Banks, but said he was more interested in property development.
Channel 4 News has seen documents prepared by a property developer, who was unaware of the pending investigation, encouraging Mr Banks to invest in the two property schemes called Bay Ridge in Port Elizabeth and Mthatha Cosmo in Mthatha.
A letter dated August 24, 2017 and addressed to Mr Banks describes him as a “potential strategic stakeholder” and propose an investment of around half a million pounds in each scheme.
Emails show how Arron Banks then helped arrange a trip to the UK for the general, his adviser Mr Njeke, and the developer, who says the purpose of the visit to make the investment pitch to Mr Banks personally.
General Galawe says Mr Banks offered to pay for a visa application for him to visit the UK, but says he paid for the trip himself.
In October 2017, four weeks after Mr Banks agreed to arrange the visa for the general, he arranged the signing of a formal affidavit in which Mr Banks made allegations of fraud against Chris Kimber and requested the Hawks carry out a criminal investigation.
An investigation into the allegations was formally opened in December 2017.
Mavuso Msimang, a former South African civil servant who is now a leading anti-corruption campaigner, told Channel 4 News: “Without doubt it is an act of corruption. Absolutely.
“I am very certain that if these facts were established, these acts are punishable.
“It is an offence. This person who is being investigated is a former business partner of Arron Banks with whom he’d fallen out. Oh absolutely.”
The code of conduct for South African government employees says they are not allowed to accept gifts totalling more than 350 rand a year – around £20.
Britain’s Bribery Act, meanwhile, makes it an offence to approach any foreign public official with an offer, a promise or a gift. Anyone found guilty of doing that faces up to ten years in jail.
In response to this story, Arron Banks accused Channel 4 News of engaging in a smear campaign.
He told us that while General Galawe had opened the case, it had been transferred to head office under a new investigating officer.
Three hours later, he changed his story and said Galawe had never been involved. The investigation, he said, had been handled from the start by Hawks HQ in Pretoria.
Arron Banks also denied having had any business dealings with General Galawe.
He insisted that his complaint against his former business partner was still being investigated. The police told us otherwise.
General Galawe told us his office had never been involved in any investigation to do with Arron Banks or his ex-business partner. He denied any wrongdoing, breaking the law or breaching any code of conduct.