I believe the idea is that if only the UK government could subsidise the shipbuilding industry enough then it could compete on the world stage. We'll end up spending billions, tens of billions even, to support a 19th century industry in the face of economic inevitability..
If the government was capable of such largesse, I would prefer to see it invested in the national infrastructure and/or the industries of the future but that's just me.
It seems that there is a section of the left wing who seems to want to return to the industries of the 1950's (coal mining, shipbuilding and so on)