BP's shares have been dented following the shock resignation of its boss amid allegations over "personal relationships with colleagues".
Bernard Looney's departure as chief executive of the British energy giant last night came less than four years after he was appointed to the role.
The 53-year-old, who was paid more than £10m in wages, bonuses and other benefits last year, is said to have failed to fully disclose details of the relationships as required by the company.
BP said in a statement that Mr Looney was standing down "with immediate effect".
It added: "Mr Looney has today informed the company that he now accepts that he was not fully transparent in his previous disclosures.
"He did not provide details of all relationships and accepts he was obligated to make more complete disclosure."
The company revealed it first "received and reviewed allegations" back in May 2022 which related to "Mr Looney's conduct in respect of personal relationships with company colleagues".
It added: "During that review, Mr Looney disclosed a small number of historical relationships with colleagues prior to becoming CEO. No breach of the company's code of conduct was found.
"However, the board sought and was given assurances by Mr Looney regarding disclosure of past personal relationships, as well as his future behaviour.
"Further allegations of a similar nature were received recently, and the company immediately began investigating with the support of external legal counsel. That process is ongoing."
A spokesperson added: "The company has strong values and the board expects everyone at the company to behave in accordance with those values.
"All leaders in particular are expected to act as role models and to exercise good judgement in a way that earns the trust of others.
"No decisions have yet been made in respect of any remuneration payments to be made to Mr Looney."
BP's chief financial officer Murray Auchincloss will replace him as chief executive on an interim basis.
Shares fell by 1.7% at the market open in London on Wednesday morning - matching the reaction on US markets the previous evening. They slipped further during trading and were down 2.7% at the close.
Mr Looney took office in February 2020 with a vow to reinvent the 114-year-old company, including with plans for it to achieve zero net emissions by 2050.
He replaced Bob Dudley, who had steered BP through the aftermath of the Deepwater Horizon spill in 2010.
Mr Looney had spent his entire career at BP after joining as an engineer aged 21 back in 1991.
Edward Moya, a senior market analyst at OANDA, said: "This was unexpected and could raise doubts to BP's transition towards renewable energy.
"BP share prices might not get rocked that hard as CFO Auchincloss appears poised to take over. Whoever becomes the permanent CEO will have a greater impact on what happens to BP's stock."
BP recently recorded a big drop in profits in the first half of its financial year, after energy prices fell from the highs seen following Russia's invasion of Ukraine.
The oil and gas giant reported net profits of just over $2.5bn (£2bn) for the three months to the end of June.
The figure was half the $5bn (£4bn) profit achieved in the preceding three months and was down sharply on the same period last year, when it made $8.45bn (£6.5bn).