The company is to invest €15 million (£13m) into developing a new pub and 98-bedroom hotel in Dublin city centre, which will create around 200 jobs.
Development work at the site, currently a row of derelict properties in Camden Street, will begin in February, with the pub and hotel set to open in early 2019.
Announcing the investment in the Republic of Ireland’s capital, Martin, who founded the chain in 1979 as a 24-year-old, emphasised the commercial rationale for the bumper investment.
“We are looking forward to developing the site into a fantastic pub and hotel,” he said.
“It will be the biggest single investment undertaken by Wetherspoon and will result in our largest hotel alongside a superb pub.
“Our pubs in the Republic of Ireland are thriving and we are confident that the pub and hotel will be a great asset to Dublin and act as a catalyst for other businesses to invest in the city.”
The company has five pubs in the country, including The Linen Weaver in Cork and The Three Tun Tavern in Blackrock. The new Dublin pub will be set over two levels and, unusually for Wetherspoon, will feature a beer garden.
Some historical aspects of the derelict buildings will be retained and restored. These include a circular stained glass window which was crafted by Earley & Company (church decorators and stone carvers) who were based at the site.
Martin owns 28 per cent of Wetherspoon, whose 950-plus pub estate in Britain includes about 70 outlets in Scotland. He has repeatedly accused the EU of being an undemocratically elected body sustained by political elites.
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He has used several company updates to criticise the likes of German chancellor Angela Merkel, former French president Francois Hollande, European Commission president Jean-Claude Juncker and former UK Chancellor, George Osborne.
Saying he felt vindicated that he made the right call in campaigning against Britain joining the euro in 1999, Martin told Scotland on Sunday last year: “Too many of these politicians have been loved since they were aged four, top of the class, they have been told they are brainier than anybody else, and then they find they only have the same vote as the riff-raff. They like Brussels and are predisposed to the EU.”
Wetherspoon, whose Scottish pubs include the Alexander Graham Bell in Edinburgh and The Carron Works in Falkirk, said in a trading update last month that like-for-like sales climbed 4 per cent in the third quarter to 23 April, while total sales rose 1.3 per cent.
The group forecast a “slightly improved trading outcome” for this financial year thanks to better than expected year-to-date sales, with same-floorspace sales up 3.5 per cent and total sales up 1.4 per cent.
However, Martin repeated his warning that the pubs sector remains under pressure from higher staff wages, higher energy bills, alcohol duties and cheap beer sold by supermarkets.