A decade ago, the highly prized “king of fish”, the bluefin tuna, was taken off menus in high-end restaurants and shunned by top chefs, amid warnings by environmentalists that it was being driven to extinction. Recent assessments of eastern Atlantic bluefin tuna, which can grow to the size of a small car and live for up to 40 years, have shown much healthier populations.

But now conservationists and scientists are warning that the largest and most valuable tuna species could once again be under threat if a Japanese bluefin fishery in the eastern Atlantic Ocean is awarded an internationally recognised “ecolabel