What significant event did HMS Opportune attend in 1977?
Reference
Moonshot's Answer
In 1977, HMS Opportune attended the Silver Jubilee Fleet Review off Spithead as part of the Submarine Flotilla. This significant event was held to celebrate Queen Elizabeth II's 25th anniversary on the throne. The review featured a gathering of many ships to be formally inspected by the Queen, and HMS Opportune was one of them. The image of HMS Opportune, an Oberon-class submarine, can be seen here.