Critics argue that “taxpayer bailouts” should not boost profits for an industry which they claim has dumped 300,000 tonnes of pollution in lochs and harmed marine wildlife. Campaigners question whether fish farming in its current form is environmentally sustainable.

Government and industry, however, point out that fish farming is worth £885m a year to the Scottish economy and contributes £94m in taxes. The industry disputes the level of pollution and says that lochs have “good” water quality.