An outstanding grammar school has suspended two teenage girls over a peanut prank which the school says could have killed their teacher with a nut allergy.

Alexandra McDonald, 16, and Maddie Colley, 17, said they were looking for a blazer during a free period at Rochester Grammar School in Kent, when they were accused of putting crushed nuts near a teacher with a severe allergy.

Both girls, who are due to sit their mock A-Level exams, have been suspended for 20 days by the school after the incident, which teachers claim could have caused serious harm or even death.

Although they have denied being part of the prank and claim they saw the crushed food on the floor but thought nothing of it, the teenagers’ exclusion means they will now sit their exams at a neighbouring school whilst in isolation.

One of the girls, who hopes to attend the University of Kent, took a £595 lie detector test to protest her innocence. She said the results show it proves just that.

"I'm gutted. When I was told I was going to be excluded I was shocked, I couldn't speak,” said Miss McDonald.

“I've always wanted to be a teacher but this makes me think it's not something I want to do, if this can happen to an innocent person. It definitely was not me.