Glasgow City Council is seeking to overturn a landmark ruling that an atheist teacher was the victim of religious discrimination.
David McNab hoped for a job at the Catholic school
A tribunal last year ruled in favour of maths teacher David McNab who said he was not considered for promotion at St Paul's Roman Catholic High School.
Mr McNab received £2,000 compensation from the city council.
But the council told an appeal tribunal there was a genuine need for the candidate to be approved by the church.
It told the tribunal in Edinburgh that the discrimination was justified and that the compensation was excessive.
The original employment tribunal heard that Mr McNab was told he could not be considered for the job as it required Catholic approval.
It ruled that Mr McNab's right to freedom of religion or belief had been breached.
Brian Napier, QC for Mr McNab, argued Glasgow City Council had failed to show his client had not been approved by the Catholic Church.
The hearing continues.
Last year's employment tribunal ruling was the first of its kind since new laws banning such discrimination came into effect in 2003.