Headteachers have braised concerns that bright teenagers could miss out on places at the UK's top universities due to last summer's GCSE English controversy.
In a letter to vice-chancellors, Mike Griffiths, president of the Association of School and College Leaders (ASCL), said he wants reassurance that applications from high-achieving students who missed out on an A grade in their English language GCSE will not be consigned to the "reject" pile.
Over-subscribed university departments which decide to use GCSE English as a filter when making offers are in danger of inflicting a "second injustice" on these students, Mr Griffiths claimed.
In his speech to the ASCL's annual conference in central London, Mr Griffiths, who is also head of Northampton School for Boys, said: "I am asking for reassurance that a B grade in English language will not mean some of our most talented students fall foul of an arbitrary filter.
"At my school there are five students who achieved an A or A* in all subjects - apart from, against expectations, English language. I want to be able to reassure those students that an application to Oxbridge or a Russell Group university will not automatically be consigned to the 'reject' pile."
A row broke out over English grades after last summer's GCSE results were published, with school leaders claiming that tens of thousands of teenagers unfairly received lower-than-expected grades in the subject after grade boundaries were moved between January and June.
An alliance of pupils, schools and local councils took their case, against two exam boards - AQA and Edexcel - and the exams regulator Ofqual, to the High Court, calling for the grade boundaries to be changed. But last month a High Court judge ruled that, while teenagers who fell foul of changes to GCSE English were treated unfairly, the exam boards and Ofqual did not act unlawfully, and dismissed the alliance's challenge.
Mr Griffiths said he has written to vice-chancellors at Russell Group universities - considered the top institutions in the country - urging them not to use an A grade in English language for this year group when offering places on degree courses.
He said: "I recognise that, in order to sift applications, departments may regard a top grade in English language as an essential precursor to success. I believe that if universities were to rely on such an unreliable and flawed examination outcome, you would be in danger of not only inflicting a second injustice on these students but also denying places to some of the most talented youngsters in the cohort."
A Russell Group spokeswoman said they were awaiting ASCL's letter, but added that it is down to individual universities to decide on admission policies.