The head of the Royal Navy has abruptly stepped down from his role with immediate effect citing ‘personal reasons’. The move left the Royal Navy stunned as Sir Ben Key, 59, was due to speak at the First Sea Lord's Sea Power conference in London next week.

The Sea Lord Admiral notified the chief of defence staff Admiral Sir Tony Radakin and defence secretary John Healey last autumn of his intention to step down this summer but his departure comes earlier than expected. The unexpected move means the conference next week has been postponed indefinitely. Offering their “sincerest apologies” the Council on Geostrategy described Sir Ben's departure as "unanticipated" in an email.

The email read: "It is with sincere regret that we must inform you that the First Sea Lord's Sea Power Conference 2025 has been postponed.

"As you may already be aware, this decision follows the news that the First Sea Lord has had to step back from his duties for personal reasons. On behalf of both the Royal Navy and the Council on Geostrategy, we offer our sincerest apologies for any inconvenience this may cause."

According to a report in the Financial Times, he is not stepping back due to the Government's Strategic Defence Review.

However, a Navy source told The Telegraph: "A cynic might think he has seen the review and wanted to be out before s--- hits the fan.”

Sir Ben had served in the Navy for a little more than 40 years, beginning his career in 1984, initially qualifying in helicopters and as a Principal Warfare Officer. His appointment to the post of First Sea Lord came in November 2021.

When his retirement was confirmed last year, it came as a surprise to many in the military who had tipped him to be the next Chief of the Defence Staff.

However, a source close to Sir Ben told The Telegraph that he was unhappy with the state of the Navy. The source said: "He has stared down the bottom of the barrel and doesn't like what he sees."

Those familiar with the matter are insisting that after 41 years of service Sir Ben is entitled to step down.

During his long career he has commanded four ships, including the mine hunter HMS Sandown, the frigates HMS Iron Duke and Lancaster, and the aircraft carrier HMS Illustrious.

A permanent successor is believed to be named in a matter of weeks with the Ministry of Defence having already interviewed candidates to replace Sir Ben.

Vice Admiral Sir Martin Connell has taken command in the interim and is thought be in the frame as his successor.