PASS rates at Higher have fallen to their lowest level for four years at a time of education cuts, teacher shortages and reform of the qualifications system.

The decline from 79.2 per cent in 2015 to 76.8 per cent was revealed as more than 135,000 pupils across the country received their exam results.

The Scottish Qualifications Authority (SQA) revealed that pass rates were also down for National 4 and National 5 qualifications - the latter a year after the removal of coursework marked by teachers.

However, pass rates for Advanced Highers rose half a percentage point to 80.5 per cent.

There was also concern after it was revealed there were 12,000 fewer entries for National 5 courses in 2017/18.

The Curriculum for Excellence has previously been blamed for reducing the number of qualifications available because schools spend more time developing wider skills in the first three years of secondary.

Recent figures show more than £400m of spending has been cut from Scotland’s education system since the start of the decade as part of a wider public spending squeeze. Scotland's curriculum and exams have also been extensively revamped in recent years.

John Swinney, the Education Secretary, said pass rates remained stable despite the fluctuations and a drop in the school roll.

He said: "It is important to remember that we will always see slight variations in pass rates and the results show that we have a robust, credible assessment system in place.

"It is clear that our young people have performed strongly, against rigorous standards, and are now in an exciting position to decide what they go on to do next."

Dr Janet Brown, chief executive of the SQA, said the figures showed the exam system was working well.

"There are fluctuations year on year, but Higher is very stable. There is some movement in individual subjects, but that is what you expect in a stable qualifications system where the group of candidates changes from year to year.

"If attainment constantly goes up the obvious statement that is made is that we are dumbing down the assessments, but what we are seeing here is a stable system."

Opposition parties congratulated pupils, but voiced concern about falling attainment levels at Higher and National 5.

Liz Smith, education spokeswoman for the Scottish Conservative Party, accused the Scottish Government of "complacency".

She said: "There's no escaping the fact that, for a government which claims its priority is education, these are disappointing statistics.

"There has been no improvement in overall attainment across the board and these statistics confirm there are still major issues about the mix between National 4 and National 5 qualifications."

Iain Gray, education spokesman for the Scottish Labour Party, said the "real concern" was that falls in attainment were becoming "clear trends" over a number of years.

He added: "It would appear that years of cuts to school budgets and teacher numbers, along with the narrowing of the curriculum and reduced course choice, are now having an impact on exam results."

Ross Greer, education spokesman for the Scottish Greens, said: "Careful consideration needs given to this third consecutive drop in Higher passes and the potential of it becoming a trend."

However, Larry Flanagan, general secretary of the Educational Institute of Scotland (EIS), said teachers were continuing to deliver despite the pressures facing the educational system.

He said: "Teachers have continued to go the extra mile to provide support and encouragement to their pupils whilst dealing with ongoing concerns of excessive workload and deteriorating salary values.

"This year's results show both Scotland’s pupils and schools continue to perform well, despite the many challenges affecting education and teachers today."