knife-edge

His knife-wielding arm buckled and somehow—it was good luck for Ashton, but bad for Simon!—hooked itself ’round Simon’s neck, with the gleaming knife edge pressed against the young bard’s throat.

"I had five seizures brought on by extreme stress because I was just living on a knife edge all the time," she added.

On this ground 20 years ago, another epic series was on a knife edge.

But South Africa roared back into the contest in the second half of the day as Australia collapsed to 144-8 - a lead of 218 - to leave the match on a knife edge.

"I've never played a golf course as hard. Every shot is on a knife edge."