Part of the TOBA with BAES is a commitment to rationalise shipbuilding capacity to a sustainable level post-QEC.
In essence that means shutting one or more of Scotstoun, Govan and Portsmouth (shipbuilding facility only). Scotstoun and Govan are interdependent, so what it actually means is that post-QEC (and actually in something like 2 years time), either Portsmouth shipbuilding facility or both Clyde yards will close.
You can explain why you'd love to see a "huge spanner thrown in the works" any time now....