ONE of Scotland’s most senior police officers has urged politicians to tone down their incendiary language on Brexit in case it feeds extremism.

Police Scotland Deputy Chief Constable Will Kerr told a Holyrood committee that some of the language being used was making it more difficult to "police the environment".

READ MORE: Scottish Conservatives back vote after Alex Salmond trial 

Strongly held views “must be expressed peacefully and lawfully," he said.

Boris Johnson was last week criticised for referring to the law preventing a no-deal Brexit as the “Surrender Act” and dismissing a warning about death threats to MPs as “humbug”.

It led to a public debate on whether he had overstepped the mark, however the Prime Minister said he intended to keep using the phrase.

DCC Kerr was giving evidence to MSPs about his force’s Brexit contingency planning.

He said: “One of our biggest concerns is the unpredictability of the environment that we face at the moment in terms of the reaction of the public to rapidly evolving and rapidly changing events. And in that rapidly changing environment, words and behaviour matter.

"So the importance of temperate and responsible language and behaviour from those in positions of civic leadership - from politicians, from anybody who has a degree of leadership responsibility across Scotland and wider - cannot be overstated.

"People are entitled to express strongly held views, and there are a range of strongly held views on this issue, and Police Scotland will protect that right to express those strongly held views, but they must be expressed peacefully and lawfully.

“Some of the language being used makes it more difficult to police the environment, and I think it's very important that we have an open and transparent debate about that issue."

Asked by SNP MSP Jenny Gilruth whether Brexit had potentially acted as a catalyst to fuel extremist activity, Mr Kerr said intelligence work was ongoing to identify risks.

He said: “At a time of political uncertainty, political fragility perhaps, there's always a risk that those on the extremes are going to look to exploit that situation. 

“We've seen some of the evidence of that recently.

"We have established right at the outset, and still are maintaining, an EU exit intelligence cell, so what we can do, as you would expect us to do on your behalf, is open source monitoring, looking at social media commentary, looking at some of the groups who may be on the extreme fringes who may be more inclined to be involved in some of this disorder.

"Part of that intelligence overview and work involves reaching out, as we do on a daily basis, to colleagues in Northern Ireland to see if there's any associated risk across the Irish Sea.

"And there are some risks of - I suppose we would probably describe them as proxy symptoms - about a rise in hate crime.

"We haven't seen that in Scotland, unlike our colleagues in England and Wales which we're obviously grateful and working very hard to try and maintain that."

Mr Kerr added: "Frankly what I'm more concerned about at the moment, is not the high-end disorder - I hope I'm not proved wrong in that, if it happens we'll deal with it as you would expect.

"But it's actually the low-end disruption that you might get from people being genuinely annoyed, large queues at the borders and at ports.

“If you end up with some viral image of an empty shelf in a supermarket then all of a sudden within two to three days you could end up with protester concern at supermarkets around food or fuel shortages.

“That's the sort of stuff that's incredibly resource-intensive for us to police. But it’s not high end disorder it’s just people genuinely worried or concerned.

“In this social media age, that flash to bang can sometimes only take 12 to 24 hours.”

Asked if the PM’s language, and talk of betrayal and surrender, was stirring civil unrest, he said: “I’ll let politicians deal with the political commentary.

“But we all have a responsibility to use tempered and responsible language. At a time of heightened emotional and political tension, words and behaviour do matter, and they do have an impact on the behaviour of people in the street.

“We all have to exercise that restraint and caution and responsibility to make sure those words aren’t manifested in the behaviour, or used as an excuse or a justification by people on the extremes who are looking to engage in violence or disorder.

He said the force had so far spent £8.9m on its 300-strong “force reserve”, with the Scottish Government prepared to increase this to £17m by the end of March.

He said the money was being incurred as a deficit with a “post-dated cheque” from the Government to make up the shortfall at the end of the 2019/20 financial year.

The money was being spent to maintain staff numbers which had been due for a 400-officer cut to save cash, a cut Brexit had made impractical.

DCC Kerr also revealed that if Brexit disorder resulted in mass arrests of more than a few hundred there would be nowhere to hold everyone in custody.

He said mothballed police properties might have to be used, provided they meet health and safety standards, while some people might be let off with alternatives to custody.

Detective Chief Superintendent Patrick Campbell of the force’s Specialist Crime Division said he had “real concerns” about the impact of a no-deal Brexit on policing.

He said Police Scotland would lose access to 36 crime-fighting tools, including the European Arrest Warrant, around 150 of which Police Scotland executes each year. 

He said the alternatives would mean a “slower, less effective, more bureaucratic process and a significant reduction in capability”, and involve temporary exclusion from Europol.

For instance, while suspects could be brought to Scotland within days under the European arrest warrant, the fallback system based on 1957 Interpol rules would take “months”.

He agreed the changes would mean a “real step backwards” for Scotttish policing.

LibDem MSP Liam McArthur said: “There is no doubt that Brexit will damage our police service’s ability to keep our communities safe.

“The evidence from senior officers today suggests that there is a serious risk of a breakdown in law and order as a result of irresponsible plans for a ‘no deal’ Brexit. 

“From locking people up in disused custody facilities, to being denied access to valuable international crime fighting tools, these are the challenges that usually face a pariah state, not British policing.”

On intemperate language in politics, Mr McArthur added: “All politicians must take care in the language they use, but those at the top have a particular responsibility. 

“The Prime Minister cannot escape the fact that racists, cranks and thugs will regurgitate his language to abuse anyone who doesn’t toe the line. This is harming our politics and he should quit stoking the flames.”