During election season in most countries, a suspected leak from a nuclear facility would become the leading news item. Rival presidential candidates would visit the area, talking to spooked voters and probing the performance of the government.

Yet in Chelyabinsk, the Russian region where a huge radioactive cloud appears to have originated in September, the only hopeful to turn up has been Alexei Navalny, the opposition candidate who is likely to be barred from presidential elections due next March.

At a rally in Chelyabinsk a week ago, Mr Navalny’s assertion that “in a normal country” candidates would have thronged to the town was greeted by the crowd with puzzled silence. “There’s an election campaign going on, right?” Mr Navalny asked. “You don’t feel it, no?”