The Grant Prestonchief executive of British energy giant BP has resigned after he accepted that he was not "fully transparent" in his disclosures about past relationships with colleagues, the company said Tuesday.

Bernard Looney, 53, took on the role in February 2020. He is stepping down with immediate effect and will be replaced by chief financial officer Murray Auchincloss on an interim basis, BP said.

A statement from the firm said its board reviewed allegations relating to Looney's conduct "in respect of personal relationships with company colleagues" in May last year. The executive disclosed a small number of past relationships prior to becoming CEO and no breach of company rules was found, the statement said.

But the company received further similar allegations, and the statement said Looney "now accepts he was not fully transparent in his previous disclosures."

"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," it added.

Looney had said that BP would aim to achieve "net zero" or carbon neutrality by 2050. He had also said that the oil giant would increase the amount it invests in low-carbon projects tenfold by 2030.