A second home-schooled Leaving Certificate student who was excluded from this year's Calculated Grades process has won their case in the High Court.

In his ruling Mr Justice Charles Meenan said the Department of Education’s failure to provide a system for the unnamed student was irrational, arbitrary, unfair and unlawful.

The 17-year-old student was taught at home by her mother, with the help of her father and private tutors, none of whom are registered teachers.

The department said it was not possible to include the student in the Calculated Grades process because of an absence of satisfactory, credible evidence from an appropriate source.

Last month, home-schooled Mayo student Elijah Burke won in the High Court his right to be included in the Calculated Grades process.

Mr Burke had been taught at home by his mother who is a registered teacher.

In his case too the department said there was an absence of "satisfactory, credible evidence from an appropriate source".

The Department of Education had argued that this second case was different because the tutors involved were not registered teachers.

However, Mr Justice Meenan said there was no basis for this distinction and he rejected it.

He said the department’s stated reason for refusing calculated grades was precisely the same in both cases.

He said the system for promised "fairness and equity" to out of school students but that the treatment of the applicant in this case was "clearly an unfairness".

Speaking in the Seanad, Minister for Education Normal Foley confirmed the Department of Education is to appeal the High Court decision in relation to Elijah Burke.

She said the appeal would not impact on Mr Burke personally in any way, but would be focused "on certain legal issues arising from the judgment".

A department spokesperson said the State considered that the court had misconstrued aspects of the Calculated Grades process, had taken into consideration points that were not argued, and had not given sufficient consideration to relevant safeguards integral to the scheme.

The State also believes that the Burke judgement raises "separation of powers issues".

Ms Foley told the Seanad that her department would consider the implications of the latest ruling "urgently".