Few people take as long a view as Clyde shipbuilders. The men and women who design, build and fit out some of the world's most complex warships cannot afford not to. After all, it can take decades between the first electronic draft of a new frigate until the last of its line enters service. And that ship can stay on active service for decades longer.

That is why so many workers are worried about BAE Systems' decisions first to drop plans first for a £200m "frigate factory" and then for a less sophisticated giant shed at Govan. They take comfort that they still have a big Ministry of Defence order for the next two decades, for eight Type 26 frigates. But they are thinking way ahead and asking two questions. The first is whether last yards on the Upper Clyde, BAE's Govan and Scotstoun, have to capacity to bid for anything other than those eight ships while the Type 26 programme is under way. The second is whether the yards will have the infrastructure, the plant, to be able to compete for new orders, not just from the MoD, when the frigates are finished.

One insider was pretty downbeat. "Type 26 will be built using a 'make do and mend' approach using infrastructure at Govan that was last modernised in the early 1990s by Kvaerner," he said, referring to a former owner. "It's stunningly short sighted and restricts the Clyde's long term potential. The Clyde now has no extra capacity to build anything more than Type 26. It can't build for export in tandem as they've demolished the facilities."

Scroll back two years and the mood music was very different. In early 2014 - just as the Scottish independence referendum debate was ramping up - BAE Systems was enthusing about putting up a a state-of-the-art £200m-£300m "frigate factory". Back then, to be fair, it was assumed the MoD would be ordering13 frigates, not eight. There was even talk of more export capacity. Charlie Blakemore, of BAE Systems, could not have been more upbeat, "It will provide a capacity that is world-class. We will be able to compete in a more level playing field," he told The Herald. A frigate factory had a controversial edge: it meant the Govan site would be surplus. Some saw that as an advantage, freeing up capacity. Others thought it threatened an historic yard, the old Fairfields, just as it became totemic in referendum politics.

But Mr Blakemore had a Plan B: instead of a frigate factory he was also suggesting £100m in investment at both yards, building ships at both. Crucial to that was a giant new outfitting shed and other major works at Govan. However, Mr Blakemore thought his own Plan B was "sub-optimal".

So he favoured the single investment at Scotstoun, include a 360 yard-long new dock hall capable of building two ships at once - all indoors. Such a facility would churn out warships one-third faster than across both yards, making the navy's new Type 26s "significantly cheaper" - and more exportable. Mr Blakemore's enthusiasm was genuine. BAE Systems even knocked down its existing dock halls - where it had built frigates for export - to make way for it. Then, in 2015, the plans were quietly dropped.

Nobody made a big fuss. Now the Plan B has also effectively been binned. True, BAE Systems is still investing. In fact, official sources suggest they are putting £100m in to the two yards. But they are not building the kind of state of the art covered shipyards now standard in advanced economies. So why no new big shed? Because the drumbeat, the pace at which they were going to make the Type 26s, has slowed. Instead of one every year, they will make one every 18 months. The firm can get away with making the ships this way because its only customer, Defence Secretary Michael Fallon, is happy with this. Are Scottish politicians? And if they aren't, would they be willing to support in infrastructure investments rejected by the MoD?