Diageo’s Brewhouse No.4 is the “largest stout brewery in the world” and is located on the St. James’s Gate site.

It uses new technology and processes to “minimise energy consumption and greatly reduce environmental impact”.

Ivan Menezes, chief executive of Diageo, speaking at the opening recently, said: “This is a great day for Diageo and a great day for Guinness, one of the most iconic brands, not just in Ireland, but around the world.

“Our decision back in late 2011 to invest in St James’s Gate represented a €169m vote of confidence by Diageo in Guinness and in our beer business. It also represented a major vote of confidence in the Irish economy itself.

“Diageo’s operations in Ireland support the employment of 20,000 people in the Irish economy, not least through our purchase of goods and services to the value of €350m a year.”

Taoiseach Enda Kenny, opening the brewery, added: “The government’s plan for recovery will see continued support for our indigenous export orientated food and drink sector which provides jobs across the island of Ireland.”