Which British yards build submarines and supercarriers

If the British Empire had not declined, would Vickers-Armstrong build nuclear submarines and which yard would build Royal Navy supercarriers?

Barrow would likely remain the submarine center and Cammell Laird the carrier yard, though the companies could still merge or change names.

Enduring shipyard capability matters more than the survival of a particular corporate name. Vickers-Armstrong's Barrow yard already anchors British submarine construction, so the same industrial site would likely build SSNs and SSBNs in a stronger empire. Cammell Laird is identified as the likely supercarrier builder because it controlled a dry dock large enough for the proposed hull. Even a prosperous state could not guarantee that Vickers-Armstrong itself avoided mismanagement, merger, or reorganization. The shipyard's facilities and workforce are the continuity on which the proposed submarine and carrier programs depend.