JD Wetherspoon is pushing ahead with plans to ban smoking in all its pubs, despite a 20% plunge in profits in recent months.

Chief executive John Hutson said: "Three-quarters of people in the UK don't smoke. We think there's a big opportunity to attract back customers who have stopped visiting pubs because of the smoke, helping to replace those we lose because of a ban."

By May the company will have banned smoking in 10% of its pubs, with the whole 650-strong managed estate becoming smoke-free by May 2006.

Hutson claimed the performances of its three existing no-smoking pubs showed it was a popular move. He said all three had seen food sales increase their contribution beyond the company's average of 25% of turnover since going smoke-free.

But while Wetherspoon's might be pinning its future strategy on smoke-free pubs, it has had a tough six months to 23 January 2005.

Slow trading saw pre-tax profits fall 20% to £22.3m, compared with £27.8m in 2003. The company's profits were also hit by an exceptional charge of £8m, which includes the higher-than-expected start-up costs of a new central distribution centre and the forthcoming sale of 16 underperforming pubs at a loss.