Scotland has slipped down a notional league table of world economies by overall well-being, a researcher has suggested.

Economist John McLaren blamed the crash in the global oil price and disappointing results in controversial international educational rankings for the country's relative decline.

Mr McLaren, who formerly held a visiting position at Glasgow University, used figures for economic, health and other measures to see how Scotland would rank on the OECD's Index of Social and Economic Well-being, which was published earlier this year.

Scotland, in his league table, fell from 16th to 20th behind France, Korea and Belgium while the UK stayed put at 12th place.

Mr McLaren, an outspoken and regular critic of the SNP, highlighted that Scotland, Wales and Northern Ireland had not performed well in the last decade under devolution.

He said: "This index goes beyond a simple measure of GDP growth in trying to determine relative changes in well-being across most OECD countries.

"The poor results over the decade to 2016 for Scotland, Wales and Northern Ireland suggest that devolution has not acted a a spur for improvement in these areas.

"However, to expect such a positive contribution in what might still be seen as a ‘learning’ phase may always have been

overly optimistic."

The OECD Index - which includes the world's most advanced or large capitalist economies - is made up of real GDP, adjusted for prices, educational performance, employment and life expectancy.

It is not clear what bearing Devolution would have over the crash in the oil price, which has cost Scotland and the rest of the UK tens of thousands of North Sea jobs.

Devolved governments do have responsibility for administering health and education, though experts always stress it is impossible to detach these measures from overall economic trends.

Educationalists, moreover, disagree on whether so-called PISA rankings of international comparisons in education are meaningful. Scotland does well in such rankings but is slipping.

Mr McLaren blamed reforms for the last decade for what he sees as a all in relative performance.

On health, where life expectancy figures are less open to challenge, Scotland is doing badly. Scots are living longer but numbers are not rising as fast as those for parts of Eastern Europe.

Mr McLaren said: "Scotland’s lowly position in terms of life expectancy is not a judgement on the performance of the

NHS in Scotland but rather takes into account wider traits, including preventative health measures, personal preferences, housing.

"While it is difficult to be exact in terms of what to recommend, it

does seem that current practice has had little impact in improving Scotland’s relatively poor international performance on this measure."