Scotland’s salmon farming industry portrays itself as a clean, healthy industry, trading on the beauty of our lochs, mountains and skies. It’s “a huge Scottish success story”, it claims.

We beg to differ. We have revealed before how it has polluted our nation's lochs with pesticides, and helped to prevent the Scottish Environment Protection Agency from banning the worst pollutant - despite evidence it was doing harm.

Today we report that disease and parasites forced fish farmers to throw away a record 22,479 tonnes of salmon in 2016. Estimates vary, but the industry accepts that could be as many as ten million dead fish.

That amounts to nearly a quarter of all the young fish that started off in cages. It’s a staggering waste, and means that countless lorry-loads of rotting salmon have to be transported south to be incinerated in northwest England.

The industry is coy about exactly how much this is hurting their business, but it is presumably having a significant impact. It certainly won’t help salmon farming’s image.

The industry has always had the potential to be an environmentally friendly business that could bring real benefits to communities. But it seems to have gone down the wrong path, seeking bigger and bigger farms, more intensive production and higher profits.

It provides valuable employment in remote areas, and it has powerful friends within the Scottish Government. But it should not be allowed to get away with anything it likes.

We question whether industry plans to double business to £3.6bn by 2030 are sustainable or wise. We also hope that the promised Holyrood inquiry will delve deep, and challenge some of the assumptions made by ministers.

There is a growing consensus among critics in favour of “closed containment”, ensuring that salmon cages that would be isolated from the marine environment. That could greatly reduce pollution, protect the fish and in the long term be good for business.

Few are seriously arguing for the industry to be shut down. But for the moment it is in the dock and must answer some serious questions before it can move on.