Even better:
“Despite strong support from my fellow (Canadians, etc) I have no current plans to run for elected office…”
A safe answer, whenever a senior UK politician* is asked if they’ve any leadership ambitions, is “There isn’t a vacancy” - “yet” is unspoken, of course. Alternatively, and a bit more negative, is something like “I’m very busy with the job I’ve got.”
“I’m 100% behind the PM/Leader” can mean “That’s so s/he can’t see the knife”.
*A junior backbencher, of course, can say things like “One day, perhaps, why not? You go into politics to get things done”.