Winter elections to appoint the first police commissioners in England and Wales will be a "complete shambles", campaigners warn.
Fewer than one in five voters are expected to turn out for the November 15 ballot, according to the Electoral Reform Society.
It warned the possibility of just 18.5% of eligible adults taking part could give an unfair advantage to extremist candidates who would otherwise have little chance of success.
Katie Ghose, Electoral Reform Society chief executive, said: "This election is beginning to look like a perfect storm, which could result in the lowest turnout for a national election in British history.
"Those pulling the strings have not done their homework and as a result this election looks primed to degenerate into a complete shambles. Put simply, if the people elected to localise decision-making over how our streets are policed, do not represent local people, what is the point of having them?"