The Cabinet is divided over plans to allow "smoking rooms" in pubs. Health Secretary Patricia Hewitt suggested the compromise rather than a total ban on smoking.
But Culture Secretary Tessa Jowell has written to anti-cigarette campaigners setting out her opposition to the so-called "smoking carriage" idea.
David Blunkett and David Miliband are also determined to block Hewitt when ministers discuss the plans this week.
The "smoking carriages" will have to be sealed chambers with high-quality ventilation and self-closing doors to cut them off from public areas.
A source close to Hewitt admitted the plan was to make them "as unpleasant as possible".
The Independent on Sunday 23/10/05 page 5
The Sunday Times 23/10/05 page 5