Cabinet members are calling for a free vote for Labour MPs on a total smoking ban in public places and private clubs, warning the government cannot afford a defeat on the issue in the new year before controversial flagship legislation on education.

They have warned that the form of a smoking ban cannot be regarded as central to Tony Blair's legacy, unlike the reforms of the education system.

The chief whip, Hilary Armstrong, is resisting the free vote, arguing it will set a bad precedent since smoking cannot be genuinely classified as a personal conscience issue, and should not therefore be liberated from the party whip.

She has also told colleagues that an exemption for smoking in those public places that do not serve food was included in the party manifesto, and should therefore be subject to a whip. But ministers close to the discussions are warning that enough Labour MPs will support a total ban in public places to ensure Mr Blair's authority will be damaged in a vote.

The Tories have already given their backbenchers a free vote, making a government defeat likely. But the chances of Ms Armstrong staving off a big rebellion is made more difficult by the previous opposition to a partial ban coming from the health secretary, Patricia Hewitt, and the chief medical officer, Sir Liam Donaldson.

The all-party health select committee is expected to support a total ban in a report due before Christmas and before the bill's report stage