Those in the advertising industry were fully prepared for the spectre of a ban to raise itself at this year's Labour Party conference in Manchester, but the narrow decision at the Conservative Party conference in Bournemouth, to consider a ban on advertising and marketing to children, will have caused slack jaws in both Westminster and Soho.
After all, it is the Tories who have traditionally been vociferous in support of the free market and the freedom to advertise it.
Perhaps adland can draw some comfort from the political analysts, who reckon David Cameron is merely jumping on Labour's bandwagon in his hunt for vote-friendly policies. But the industry cannot ignore the fact that a cross-party consensus seems to be developing in favour of a ban. It is buoyed by an increasingly influential band of lobbyists and pressure groups that have scented blood and are unlikely to be mollified by a watery self-regulatory stance.
The industry has to be seen to be doing something about junk-food advertising to children. And it has some strong arguments in its defence: deprived of advertising revenue, children's TV would be reduced to a mentally unnourishing diet of US cartoon imports; meanwhile, the most popular children's TV shows are on the BBC, and are ad-free.
The problem is voicing this argument, though. If the lobbyists continue to link marketing to the growing childhood obesity crisis in the UK, it's one argument that could turn into a political platform at the next general election.
There is a dim light at the end of the tunnel. Last week's appointment of the Tory shadow minister Baroness Peta Buscombe as the new director-general and chief executive of the Advertising Association will give the industry much-needed political clout. And in the light of the Tory conference, it looks like the shrewdest move it has made in years.