Following normal practice, the name of the 'A' class sub passing through Plymouth Sound this afternoon has not been revealed.

Given that several of the class are said to be in refit and a new one, HMS Anson, has recently entered service, I think it likely that this was the Anson today. The sub was also really clean which shows it's not spent much time at sea.

Perhaps someone who knows the correct identity will confirm it. More photos and video on FB.