The SNP has been urged to honour a pre-election pledge to extend free breakfasts to secondary schools amid concern about the numbers of pupils going without food.

Only 13% of pupils in one Scottish secondary reported eating before first class and none of the 200 schools where pupils were surveyed had a rate higher than 68%.

In April last year, Nicola Sturgeon pledged to trial free breakfasts for secondary school pupils if her party was re-elected to government.

It builds on the SNP’s existing plans to expand the provision of free breakfasts and lunches to all primary children, which were announced by Education Secretary John Swinney in November.

One study by the University of Leeds found that students who seldom or rarely consumed breakfast on school days had lower GCSE grades than those who are breakfast regularly.

READ MORE: Aberdeen City Council approves extension of free school meals in secondaries

More than 17,000 pupils completed a survey, drawn up by the Scottish Poverty and Inequality Research Unit at Glasgow Caledonian University.

Professor John McKendrick, who led the research, said:”I think we just have to be alert to the fact that many teenagers come to school - for a variety of reasons - not having had breakfast in the morning.

“We are having this universal uptake in primary schools so maybe that’s something that has to be looked at in secondary schools.”

He said that while the results were still being analysed other research had shown that missing breakfast was evident in both poorer and more affluent areas, suggesting it may be “a teenage thing”.

The research also found that the number of secondary pupils eating lunch in school canteens ranged from just 9% to 75%.

Lengthy canteen queues was a common issue and researchers say the problem may be resulting in pupils leaving the school grounds for unhealthier snacks.

READ MORE: When do free school meals start for primary four and five pupils?

“Absolutely”, said Prof McKendrick. “I think there is something to be said, that unless you get the school environment right, the chances of having pupils eating meals is reduced.

“More often than not, in a whole range of schools, pupils were saying this was an issue we have to look at.

“The research found that many pupils don’t have breakfast and that heightens the importance of the food that they do have during the school day.

The reasons for not eating lunch were mainly, but not exclusively, food related. 

Cost was described as an issue in some schools while catering staff and ease of payment were described as positive factors.

In response to being asked about the trial in secondary schools a Scottish Government spokeswoman said: “Ministers are committed to funding the expansion of free school meals to all pupils in primary and special schools during this parliament, as well as introducing free year-round breakfast and lunch provision to support eligible children and young people outside of the school term.

“We, along with local authority partners, have already agreed to introduce universal free school lunches for primary 4 and 5 children backed by £42.2 million of funding, and targeted support during school holidays for all eligible primary and secondary children and young people, this is supported by £21.75 million of funding."