A fag-end measure for a fag-end government? That’s how Labour are keen to present Rishi Sunak’s plans to stop young people born after 2008 from ever being legally allowed to smoke. The Commons will tonight debate the second reading of the Tobacco and Vapes Bill, with Tory MPs being granted a rare free vote. With dozens of Conservatives expected to vote against the legislation, Wes Streeting and others are keen to depict themselves as riding to Sunak’s rescue by lending him Labour votes.

‘Rishi Sunak might be weak but Labour will not allow the Liz Truss wing of the Conservative Party to choke off the Smoking Bill today’, the Shadow Health Secretary tweeted this morning. ‘We will give our full support to this Bill so that the next generation are even less likely to smoke than they are to vote Conservative.’ With Labour backing the change and the bulk of the government offering their support, the legislation should become law later this year. The real question is therefore not whether the measure will pass but how many Tory MPs refuse to back it.

Most reports put that number as somewhere around 50, with one government source only describing it as a ‘moving picture.’ There is little real enthusiasm for the Bill among Conservative backbenchers, with Jesse Norman among the few to publicly tweet his support. ‘It’s a gradual long term reform that doesn’t affect anyone now smoking, protects young people from a dangerous addictive drug, supports the NHS and saves the taxpayer and society a fortune,’ he said this morning.

Wes Streeting is naturally seeking to exploit Rishi Sunak’s party tensions with his comments. ‘How many Trussites does he actually think there are?’ remarks one Tory. But Conservatives both inside and outside parliament will be watching today to see which among their number backs a measure that lacks grassroot support. Particular attention will be paid to likely future leadership contenders. Kemi Badenoch, the Business Secretary, is among those considering voting against the ban.

Ten years ago, Truss distinguished herself as one of only two cabinet ministers to vote against the Coalition’s plans for plain-packaging of cigarettes. That free vote offered her a chance to demonstrate her libertarian instincts and signal her disdain for the ‘nanny state’. Tonight’s division could offer the chance for Sunak’s would-be successors to do the same.