This is all about creating jobs. It would be simpler and cheaper to just purchase them new or 2nd hand from the US or UK. As France said reactionary, you only have to ask because they have nuclear subs too. All these talk about long term planning but they can't even manage the diplomacy as they back flip blaming short term political conditions.
What if in the mean time while we get delivery, changes in the global relationships between US-China or/and including Russia? Currently, looks very unlikely we are going to be at the negotiating table, we will have to suck it in and extend US foreign policy.
