Liz Truss is easy to mock, but she could do more damage than Boris Johnson ever did | Gaby Hinsliff

The Tory leadership frontrunner is a calculating workaholic who readily drops positions that no longer serve her

Liz Truss loves maths. She loves it so much that she used to fire mental arithmetic questions at civil servants during meetings, and once told an audience of female high-flyers that her best advice for their ambitious daughters was to study the subject. She loves maths so much, indeed, that she approaches political decisions like an equation to be solved. The maths professor's daughter works methodically through every possible option, including some that others would consider beyond the pale; she likes to test every argument, sometimes to exhausting lengths. (As one of her aides used to joke: what's the difference between a rottweiler and Liz Truss? A rottweiler eventually lets go.) Her logical, dispassionate mathematician's approach makes her a formidable negotiator and an unsentimental strategist, swift to abandon positions that no longer serve her.

Yet those who know her best say that with it comes a curious emotional detachment, or inability to factor into her calculations how things feel to other people, which is only now being exposed. She can be good company in private, funny and lively. But when colleagues mention her faintly awkward" manner, or even call her as close to properly crackers as anybody I've met in parliament" (Dominic Cummings, no stranger himself to being called something similar), this particular disconnectedness is often what they mean. It's shaped the campaign of the woman still most likely to be Britain's next prime minister, barring a political earthquake, and may soon shape this country's future.

Gaby Hinsliff is a Guardian columnist