BP’s board of directors faces questions over what it knew about former chief executive Bernard Looney’s personal relationships with colleagues after his shock resignation on Tuesday night. Looney stepped down after less than four years at the helm, and more than two decades with the company, amid an ongoing investigation into allegations that he had engaged in personal relationships with colleagues that were not disclosed to the board. His departure left equity markets reeling, but sources told the Guardian there was speculation about his relationships at BP long before he was made chief executive. The shares ended the day down almost 3%, or more than £2bn, to value the company at £87bn. “It has been an open secret for some time, and the BP board must have known about his reputation before he was appointed as chief executive. It’s absolute nonsense to suggest that this came to light last year,” said one senior oil industry source. According to BP, it was in May last year that it received and reviewed allegations from an anonymous source relating to Looney’s personal relationships with colleagues. Before taking up the position of chief executive, Looney disclosed “a small number of historical relationships” and gave the board assurances about his future behaviour, the company said. No breach of BP’s code of conduct was found, it added. Since then, further allegations have come to light, according to BP, and the company began a further investigation into the new claims with the assistance of external legal help. In response, Looney told the company that “he was not fully transparent in his previous disclosures” and he accepted that they ought to have been more complete, according to the company. But claims that his conduct was known to colleagues raise difficult questions for BP’s board over when they became aware of his behaviour and chose to act. “It has been going on for years,” suggested one senior energy industry source. “There are plenty of stories about his relationships with colleagues within BP. We’ve all heard them.” Another said: “What we have to remember is that he didn’t join BP a few years ago. He has been with the company his entire working life. They know him. Ultimately, this is about a corporate culture and BP’s corporate governance.” The son of Irish dairy farmers, Looney joined the company as a 21-year-old graduate from University College Dublin in 1991. As a drilling engineer, he worked in the North Sea and the Gulf of Mexico before attending the Stanford Graduate School of Business in 2004. He returned to BP with a Masters of Science in Management. “In companies like BP it’s not unusual for senior executives to spot and nurture upcoming talent. Bernard was earmarked for greater things and fast-tracked into leadership,” the source said. “The thinking was that he needed to settle down, and not shag around quite so much,” the source said. Looney married life coach Jacqueline Hurst in 2017, but the pair were separated by 2018 and the divorce was finalised the following year, three months before he was appointed BP’s chief executive. After the divorce Hurst wrote a self-published book in which she recounts the “bitter experience” of her divorce, understood to refer to the end of her marriage to Looney, which the book says ended “suddenly and without warning via a WhatsApp message”. She wrote: “I learned later that he had only married me because he wanted to get to the next level of seniority in the company he worked for and he had to be seen to be married in order to be given the promotion. Unbelievable I know, but that was the case.” A BP spokesman said at the time: “We don’t comment on the personal life of any of our people, including the chief executive.” Looney’s departure raises key questions for the company over its commitment to becoming a net zero carbon energy company by 2050. He began his tenure with a radical break from the industry’s relentless pursuit of growing fossil fuel production, setting out plans to scale back oil and gas production while growing in areas including electric vehicle charging, biofuels and renewable energy. The company said it would stick with its energy transition plan. The interim chief executive, Murray Auchincloss, reportedly told staff that “our strategy hasn’t changed”. A spokesperson for Looney said he was not available to comment.