The new chairman of NatWest is facing scrutiny over his former role with international oil group PetroSaudi, which is embroiled in one of the world’s biggest financial scandals. City veteran and former MasterCard boss Rick Haythornthwaite worked for PetroSaudi International (UK) Ltd, the oil group’s British arm, for eight years, earning £200,000 a year. The oil group is alleged to have been involved in a scheme to divert hundreds of millions of dollars from 1MDB, a sovereign wealth fund created for the benefit of Malaysia and its people. There is no suggestion of wrongdoing by Haythornthwaite, but the scandal raises questions over his judgment in working for the oil firm and whether he responded appropriately when the allegations were first raised. NatWest Group announced last week that Haythornthwaite was to be its next chair, as it copes with the aftermath of the debanking of Nigel Farage and the resignation of chief executive Alison Rose over the affair. The government owns 38.6% of the NatWest Group, but it is operationally independent. 1MDB was launched in 2009, raising billions of dollars in bonds. The US Department of Justice claims that between 2009 and 2014 individuals and corporations, including PetroSaudi, fraudulently diverted billions of dollars from the fund. The Observer has established that in 2009, when PetroSaudi boss Tarek Obaid discussed a joint venture with 1MDB aboard the luxury yacht Alfa Nero off Monaco, he called Haythornthwaite for advice once the outline of the deal had been agreed. The joint venture is now under investigation by US and Swiss authorities. Haythornthwaite continued to work for PetroSaudi for about a year after the firm was first accused of involvement in the theft of funds from 1MDB. He filled various part-time advisory roles for the group’s UK arm from 2008 to 2016. Corporate filings by MasterCard, his previous employer, show that these roles included president and chairman of the operating businesses. He left in mid-2016 after becoming increasingly concerned over the conspiracy allegations. A source close to Haythornthwaite said he was never a director or “privy to the action of the owners” and never saw any evidence of wrongdoing. In December 2015, the campaigner and journalist Clare Rewcastle Brown wrote to Haythornthwaite, challenging him over the ownership of a firm in the Seychelles that benefited from the joint venture between 1MDB and PetroSaudi. She had been leaked a cache of more than 220,000 documents from PetroSaudi’s servers that exposed the alleged financial wrongdoing, and earlier in 2015 had posted an online story about the PetroSaudi and 1MDB deal headlined “Heist of the Century”. Haythornthwaite responded: “Even if I were to be in possession of information relevant to your query, I would be unwilling to assist you in your questionable activities.” He was suspicious partly because there were claims at that time that some of the emails might have been doctored. It is understood Haythornthwaite now wishes he had offered a more considered response to a credible warning over what turned out to be a global money laundering conspiracy involving Malaysian financier Jho Low, Malaysia’s prime minister and companies including PetroSaudi. In July 2016, the US Department of Justice described the 1MDB scandal as the largest kleptocracy case it had ever handled. Sources close to Haythornthwaite say he believes Rewcastle Brown deserves credit for what she uncovered. The Office of the Attorney General of Switzerland announced in April that it had filed an indictment against two PetroSaudi managers over misappropriation of 1MDB funds. It is understood Haythornthwaite has been approached as a witness or potential witness. A proposed employment contract between Haythornthwaite and PetroSaudi International (UK) Ltd seen by the Observer says his “basic salary will be £200,000 a year” and stipulates a working week of at least two and a half days. It also says he will, subject to various provisions, be entitled to bonuses of £1m by 28 February 2011 and £1m within two months of 1 June 2014. Sources close to Haythornthwaite said various versions of contracts were drawn up between him and PetroSaudi, and that he did not receive the £2m in bonuses. Haythornthwaite did not respond to questions over what bonuses, if any, he was paid and whether he established the source of such funds. Another document, which appears to have been written by Haythornthwaite, recommended a Coutts scheme to ringfence his bonus pot offshore. A source said the proposal was never executed and would not have been considered appropriate. The source also said Haythornthwaite could not recollect ever writing such a document, and added: “His role at PetroSaudi UK was a part-time advisory assignment alongside a number of other chairmanships. He was never a director or privy to the action of the owners. “His sole focus was on the exploration and production activities of the UK subsidiary, an entity that had no board and was purely operational. At no time did he see any evidence of wrongdoing, but as rumours increased he decided to step away.” Haythornthwaite’s work at PetroSaudi was not referred to in the NatWest press release announcing his appointment. Bank officials said this was because he had never been a director at the group. His work for the oil group is also missing from his LinkedIn profile. Haythornthwaite, who will take up his new role in April, is understood to have disclosed his work for PetroSaudi before his appointment. A NatWest spokesperson said: “At no time has Rick Haythornthwaite been a director of PetroSaudi International (UK) Ltd (now PSI Group Services Ltd), as is clear from disclosures on Companies House.”