Already trailing in the polls and under heavy fire following the disclosure of lewd comments he made about women more than a decade ago, Donald Trump has also upset witches and pagans.

Republican strategists’ hopes of a better performance from Mr Trump in Sunday’s candidates’ debate could be dashed by powerful new forces beyond even his control.

A non-partisan group calling itself the World Ad-Hoc Association of Witches has pledged to “exert mental influence” on the debate which, it claims, will force the billionaire to quit the race.

It believes it can succeed where the powerful Republican figures from Ted Cruz to Jeb Bush have failed.