UK MOD has signaled to Parliament that Detailed Design and Long Lead Items (D2L2) phase for SSN-AUKUS starts next month.
This phase includes early steel fabrication and will last out to 2028. October 2028 will see a new phase begin, presumably to include Boat 1 build commencing.
The MOD has produced this long and good briefing paper on SSN-AUKUS but has spectacularly failed to advertise it in any real way and i think very few have seen it. You might want to take a look.
https://www.gov.uk/government/public...for-the-future
The AUKUS nuclear powered submarine pathway: a partnership for the future