Glanbia shares slid 7.5%, stripping around €300m from its market value, as investors showed disappointment at the company’s 2018 earnings outlook, despite it unveiling 2017 figures which showed an eighth successive year of strong growth.

Glanbia is on course to deliver on its 7%-10% growth forecast for 2017, with revenues for the year to September 6.6% higher than this time last year.

The boss of Glanbia has called for “as long a transition period as possible” following Brexit if current trading conditions between Ireland and the UK cannot be maintained.

Farmers have given a cautious welcome to Glanbia’s plan to sell 60% of its Irish dairy business to Glanbia Co-op, creating a new Glanbia Ireland joint venture in a deal worth €112m.

Shares in Glanbia rose about 1.5% after the food firm said it was paying €181m to buy two more international firms.