Managed pub operator JD Wetherpoon will have 55 non-smoking pubs by Christmas.
The company already has 25 non-smoking pubs.
It originally intended to convert around 60 pubs to non-smoking sites by May of this year, but the need to upgrade kitchens to cope with increased demand has held this back.
Like-for-like sales at the 600-plus chain are 0.5% down in the year to date, falling 0.4% in the first 11 weeks of the final quarter to 10 July.
Total company sales increased 3% to £779m in the year to date, although Wetherspoon's margins have come under intense pressure recently resulting in a 20% fall in profits in the first half of the year.
Wetherspoon will announce its preliminary results for the year on 2 September, and expects them to be in line with market expectations.
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