A school found itself at the bottom of the national GCSE tables on Thursday after a mix-up led to its English exam results not being counted in the rankings.

Blakeston School in Stockton-on-Tees was credited with only 3 percent of its pupils achieving the target of five good grades at GCSE including English and maths, instead of the correct level of 25.5 percent.

The mistake made the school appear one of the worst in the national performance tables, which are closely watched by parents seeking the best schools.

"This is quite disgraceful," said Stockton Councillor Alex Cunningham. "Blakeston School has in fact considerably exceeded its GCSE exam target."

"I will be writing to the Secretary of State for Children, Schools and Families to press his department to correct these figures without delay because this is important to both the school and the council."

Stockton Council said the school had been piloting a new English GCSE syllabus but the results had come back from examiners Edexcel a month late and missed the tables.

"It has been distressing and disappointing to receive calls from national newspapers asking us to explain our position, when in fact our pupils deserve congratulations for doing so well," said the school's headteacher Georgiana Sale.

"We feel let down, to say the least."