Students are likely to be awarded their GCSE and A-level grades this summer based on a combination of predicted grades, mock exam results, coursework and teacher assessment — with a possible exam session in the autumn for those who feel their grades are unfair, a schools leader has said.

As teenagers, parents, and teachers called on the government to explain how grades would be awarded, Leora Cruddas, chief executive of the Confederation of School Trusts — which represents academy trusts — revealed the plans in an email to headteachers on Wednesday night after meeting with education secretary Gavin Williamson and officials earlier this week.

Schools will be closed "until further notice" from Friday afternoon, except for the children of "key workers" and the most vulnerable pupils, as the government urgently seeks to curb the rapid rise of coronavirus around the UK.

In the email, seen by BuzzFeed News, Cruddas said: "Perhaps the most controversial of decisions announced today relates to public tests and exams. There will be no primary assessment.

"GCSEs and A-levels will be awarded on the basis of moderated assessment with the exam boards and Ofqual [Office of Qualifications and Examinations Regulation]. Of course this is not ideal.

"But I am persuaded there is no better option. For those young people who feel that they could have done better than their predicted grade, I believe there will be [a] mini-session in the autumn."

Williamson confirmed on Thursday that students would not be sitting exams as normal but would get their GCSE and A-level results in August. He said details of how these would be awarded would be revealed on Friday.