The company, which also owns Garfunkel’s and Chiquito, said like-for-like sales in the 20 weeks to May 20 fell 4.3% and total sales dropped 3.1% as heavy snowfall kept customers away.
The so-called Beast from the East brought snow, strong winds and icy temperatures from Siberia to the UK and Continental Europe.
Excluding the impact of adverse weaker, like-for-like sales were still down 3.1%.
The restaurant owner blamed a challenging market for the decline in sales. Like the rest of the sector, the company has been hit by tough competition and weak UK consumer confidence.
Despite the drop in sales, the company said it was “comfortable” with its performance and expects to deliver full year results in-line with current market estimates.
In early morning trading, shares rose 4.9% to 329p.
The group said it expects to see further benefit from its strategic initiatives “as the year progresses”.
Under its strategic plan, the company shut five sites in 2018, bringing the number of sites exited to 26 out of 41 planned closures.
It plans to open at least 12 new concession sites and 10 pubs this year, including the acquisition of four pubs from Ribble Valley Inns.