Wednesday’s action involves members of the EIS, the Scottish Secondary Teachers’ Association and NASUWT, and comes after a strike by primary school teachers across Scotland on Tuesday.

The unions rejected the latest offer – which would see most teachers get a 5% pay rise and the lowest earners receive 6.85 per cent.

Instead they are demanding 10 per cent, with the EIS scheduled to begin a rolling programme of strike action next week which will see members walk out in two council areas a day over a 16-day period.

Teachers have thanked parents for their “phenomenal” support as strike action closed secondary schools across Scotland – resulting in exams being rescheduled for some older pupils.

Andrea Bradley, general secretary of the Educational Institute of Scotland (EIS), highlighted the support given to teachers on picket lines as she said the Scottish Government has “miscalculated the mood of parents towards the teachers”.

She said the National Parent Forum had found in excess of 80% of parents back the strike action – being taken as part of a dispute over pay – despite the disruption caused to learning.

Ms Bradley said this would cause “some consternation” with the Government and local authority leaders in Cosla.