A Wetherspoons pub in central London in September 2017 Robert Alexander | Getty Images

British pubs group JD Wetherspoon Plc posted an 18.9 percent fall in first-half pretax profit on Friday, hit by high labor costs. The company, like most restaurant chains in the country, has been battling high staff costs, property prices and power bills as well as a move away from pub drinking by younger Britons. The FTSE 250, which relies heavily on alcohol sales at its restaurants, said on Friday labour costs increased by about 33 million pounds, accounting for the biggest chunk of overall costs. It expects results for the current financial year to remain unchanged. The company said like-for-like sales rose 9.6 percent in the six weeks to March 10, helped by good weather this year, while total sales increased 10.9 percent. The owner and operator of more than 900 pubs in UK and Ireland said like-for-like sales rose 6.3 percent in the 26 weeks to January 27.

However, speaking to CNBC's "Squawk Box Europe" on Friday, founder Tim Martin said it was important "not to overconcentrate on one six-month period." "If we'd pulled out all the stops, we could have got our profits to higher levels. Having been on the stock market for 26 or 27 years, I think it's better to take the cost sometimes and let sales do the work for you over the ensuing months or years," he said. Pretax profit fell to 50.3 million pounds ($66.7 million) from 62 million pounds a year earlier.

Backing Brexit

Asked for his views on Brexit, Martin said politicians were right to reject Theresa May's deal as it "isn't Brexit." "It's not leaving the EU, it's staying in the customs union indefinitely, and still (being) subject to European rules," he said. "Parliament has said it will implement the decision of the people — it's reluctant to do so because most of the parliamentarians are actually Remainers, but they have to do what they're told by the people in the end."