At the risk of stating the obvious, it's difficult to comprehend how a UK submarine could have achieved this. Good design and average command skills, or average design and good command skills should have ensured that this did not occur.
Interesting statement and I can't help wondering, using the parallel that often appears in respect of aircraft accidents/incidents in other threads, if this is the point at which we should be asking Mike "All the Sevens" to clarify his personal experience of handling a very large nuclear submarine in restricted waters with only the help of a single pump-jet propulsion system.
?
Astute is not "very large" in terms of nuclear submarines ..
I can categorically state that I have never run one of HM submarines aground, does that help?
At this stage, the boat should not have been anywhere near waters where there is a risk of running aground, particularly where it can be observed by all.
You probably missed the "difficult to comprehend" bit, there's a hint there somewhere.