The leader of Oxfordshire County Council has questioned whether “hard left” teachers are encouraging pupils to join protests that saw teenagers storm County Hall on Tuesday.

But a teachers’ union last night said the comments were “a professional insult to many hard-working teachers”.

Pupils from Oxford's Cherwell and Cheney schools were among those who occupied County Hall during a demonstration against tuition fees.

On his blog, Keith Mitchell, who came face-to-face with schoolchildren inside the building, described them as a “scruffy rabble” and “oiks”, and asked how they got off school to protest.

He wrote: “Locally, in Oxfordshire, how did all these teenagers bunk off their studies?

“I hope school teachers were not complicit in encouraging these children to bunk off school?

“I suspect the hard left are working up a campaign to make such lawlessness appear to be the norm.”

Cherwell School’s headteacher Paul James refused to discuss the school’s handling of the protests, while we could not contact Cheney head Jolie Kirby for comment.

But National Union of Teachers (NUT) executive member Chris Blakey said: “No teacher would encourage any student to take unauthorised absence.

“Mr Mitchell’s comments are a professional insult to many hard-working teachers.”