THE economic performance of Scotland shows devolution has not been the “disaster” claimed by Boris Johnson, according to an analysis by academics.

The Prime Minister sparked a huge backlash last month when he reportedly made the comment during a call with Conservative MPs.

An assessment carried out by ­Professor Alex de Ruyter and David Hearne of Birmingham City University, in response to his assertion, has concluded handing Scotland greater powers has been associated with a period of good economic performance.

The researchers note that in particular, a gap of more than 5% lower average weekly wages for full-time Scottish employees, compared to their English counterparts, has halved from before devolution.

But if a comparison is made with the north-west of England, average Scottish wages which were similar in 1999 have now grown to be nearly 5% higher.

Hearne, a researcher at the university’s Centre for Brexit Studies, said one key issue was how much including London in comparisons skewed the figures – because the city is much more expensive to live in.

“When you want to compare ­official figures it makes sense to ­compare two places that have broadly similar price levels – comparing Scotland with England as a whole is not right, not unless you properly adjust for prices,” he said.

“It makes far more sense to pick a region of England that has similar price levels to Scotland, and the north-west is an example of that.

“What we see since 1999 is the gap between Scotland and England in terms of wages has shrunk – but that is not necessarily the most meaningful comparison.

“If you pick Scotland and the north-west for example, what you see is ­actually Scotland has pulled ahead. So certainly your average Scot is ­better off living in, say Glasgow than Manchester.”

He added: “You can ask the ­question whether it is the devolved ­government and you might conclude it has nothing to do with the devolved government.

“But you have to start from a place that actually when you compare living standards of your average English person, Scotland looks pretty good.”

The analysis, published on The Conversation website, noted a similar pattern for productivity – with more rapid growth in Scotland compared to north-west England in the two ­ decades since devolution.

While Scotland’s productivity was previously 1.3% below the north-west, it is now 6.5% above. The researchers say the performance of the Scottish government is “far from perfect” and one area where data indicates Scotland is lagging behind is in education, with the country scoring below England in international comparisons.

But De Ruyter, who is director of the university’s Centre for Brexit Studies, added: “That is not the same as saying devolution has failed.

“It is one thing to say one particular party has not tackled this, it is very different to say devolution is a disaster – because if Scots as a group don’t like that particular set of policies, they can vote for someone else.”

The researchers conclude: “Devolution, we would argue, is only a ­“disaster” from the perspective of those such as the Prime Minister, who see the success of an SNP ­government in Holyrood (having been in power since 2007) as a threat to ­Scotland ­remaining in the UK.

“If the economic performance of Scotland relative to the English ­regions at least is anything to go by, then the UK needs more devolution and not less.”