From that article,
"Ksenija Simovic, a senior policy adviser at Copa-Cogeca, a group which represents farmers and farming co-operatives in the EU, said Brexit wasn't the primary reason but it hadn't helped.
In her view, businesses within Europe benefit both from being closer to where products are grown, and from simpler, better-coordinated supply chains.
Ultimately, she thinks, if there is a shortage of supply then the produce that is available is simply more likely to remain within the Single Market."