West of Shetland oil and gas explorer Hurricane Energy plc, which claims it made the largest new UK discovery this century, said its chairman Robert Arnott left the firm “with immediate effect.”

Hurricane also said it may move from London’s junior Aim market to “a premium segment of a recognised stock exchange.”

However, Arnott said in a statement sent to the Financial Times that his efforts to improve Hurricane’s governance standards and the company’s leadership culture had “failed to succeed due to a reluctance to implement immediate change.”

Arnott claimed “a substantial gap still exists between the company’s current standards of governance and leadership culture, and those expected of a publicly listed company,” and this prompted his decision to resign.

Hurricane said in a stock exchange statement: “Following discussions with shareholders, and in light of the company’s increased institutional shareholder base since the recent $530 million capital raise, the company is exploring a number of options, including application for admission of its ordinary shares to a premium segment of a recognised stock exchange.

“The company directors believe that a Premium Listing could provide the company with a more appropriate platform for its growth, raise the company’s global profile, potentially increase its trading liquidity and provide it with a wider addressable investor universe for its ordinary shares …

“Admission of the company’s shares to trading on the premium segment of a recognised stock exchange is subject to a decision of the board to proceed and the ultimate discretion of the relevant authorities …

“The company also announces the resignation of the company’s non-executive chairman, Dr Robert Arnott, with immediate effect.

“Dr David Jenkins, senior independent non-executive director, has assumed the role of interim chairman …”