George Green’s principal Kenny Frederick used an appearance on Newsnight on Friday to launch a stinging attack on exams regulator Ofqual.

Ms Frederick was angered by changes to the grade boundaries of English GCSE exams which affected pupils at her school on the Isle of Dogs, and used her appearance on Newsnight to confirm the school is looking into legal action in response to the changes.

Ofqual confirmed on Friday that the boundaries had been changed between January and June, but said no further action would be taken in respect of the results.

Responding to the development, Ms Frederick told Newsnight: “I’m appalled. I’m absolutely furious, as indeed are hundreds of headteachers up and down the country. This is not going to end here and there will be legal challenges.”

She also suggested that the education secretary Michael Gove had contributed to the problems, and expressed her dissatisfaction with Ofqual. “I think the exam boards have been indirectly affected by the talk about raising standards and so on.

“I personally have no confidence [in Ofqual]. We will be gathering the views of parents and of the community, who certainly will not be happy with this, and this is certainly not going to end here.”

The results, published two weeks ago, saw George Green’s buck the national trend by recording a six per cent increase in the number of children achieving five or more A*-C grades. However, Ms Frederick said that as many as 19 children at her school ended up with D grades instead of the C grades they would have received in English had the boundaries not been changed, and confirmed that the school would look into appealing some of the grades closest to the boundary.

She told the Advertiser: “They are using kids as a political football. It’s going to affect kids’ futures.”