It is the UK's newest and most sophisticated nuclear submarine, called Astute.
It has the most modern technology, including rubber tiles to reduce it's sonar signature to the barest minimum, making it virtually invisible to the enemy.
It has sophisticated electronics that make it one of the most advanced submarines in service now.
It has sonar that can scan for up to 3000 miles.
Unfortunately it seems, this same sonar cannot see below it less than a few feet. It was grounded in shallow water whilst on trials!
BBC article Nuclear submarine HMS Astute runs aground off Skye.
May be the sonar needs glasses for near-vision?
It looks like the nuclear reactor has failed as well. Looking at the image and the steam pouring out of the funnel, it looks like they have reverted back to the trusty old steam engine.
Ahh well, someone's going to get it in the neck when the Royal navy holds it's enquiry.