Speculating about names for the next British attack submarines

What names might Britain use for its next attack-submarine class?

The reply speculates about Tribal names or a B sequence and gives no settled name.

The question starts from the Dreadnought name used for new ballistic-missile submarines and asks what might follow for other boats. The reply redirects it to the next nuclear attack-submarine project with Australian and American involvement. Tribal names and a B sequence following Astute are mentioned as possibilities under discussion. Earlier R-class ballistic-missile submarines also enter the exchange. No future class name is established in the passage.