Simon Byrne says his officers could be killed if they had to patrol border checkpoints

Northern Ireland’s chief constable has said his police officers could be killed if they had to patrol border checkpoints in the event of a hard Brexit.

Simon Byrne told the Guardian he opposed officers having to patrol checkpoints on a physical border between Northern Ireland and the Republic and said officers who were already under huge strain would be placed in danger policing any checkpoints.

The Police Service of Northern Ireland (PSNI) has faced a number of recent attempts by dissident republicans to kill its officers and Byrne said only “luck” had prevented a murder, and he feared that could run out.

The chief constable, who took up his post in July, said: “People do not want a return to the images of 20-30 years ago, where, frankly, history shows us that far more police officers and 20,000 soldiers could not protect the border, so I doubt we are going to do it now.

“We are very clear here. We do not support the establishment of checkpoints or monitoring cameras right near the border and we’d be very reluctant to be drawn there because of the threat to our officers.”

Byrne moved to Northern Ireland after leading Cheshire police and serving as an assistant commissioner at Scotland Yard. He was suspended from his last job as chief constable in Cheshire after a number of misconduct allegations. He was later cleared of all of them by an inquiry. His career as a police leader seemed over but after winning the fight to clear his name, he landed the job leading the PSNI, one of the toughest in policing.

Byrne warned that the reintroduction of border checkpoints would put lives at risk: “My advice to anyone that was trying to impose it would be that we would struggle to police it without putting our officers at direct threat of attack.”

He highlighted recent events where police had been targeted: “We have had four attacks in a few weeks [where the aim] has been to kill or injure police officers going about their day-to-day duty, and by presenting fixed targets like that, it would only highlight the risk and the vulnerability.”

He said people living around the border wanted the dividends of peace and a normal life: “One of the strongest messages I’ve heard since I’ve been here is the desire from border communities for normality through that period of Brexit, if that’s what we get to.

“The border is porous. Half a field is in one country, and half in another. They want to carry on with the fact they can take the kids to school without going through checkpoints and all that sort of anxiety.

“We’re conscious that normality is important. We’re conscious that anything that looks like state infrastructure in that border area could cause problems in terms of … drawing our staff into attack.”

The PSNI is planning for a series of challenges post-Brexit. Among the scenarios, Byrne said, was “maintaining the free flow of key arterial routes”.

He said there could be “civil protest where, for whatever reason, people from the farming community, for example, block roads. We are also looking at the potential for protest in different forms, depending on which community sees Brexit in terms of winners and losers.”

He confirmed police officers from Great Britain were on standby to reinforce their colleagues in Northern Ireland and had been trained to operate in the province, as revealed by the Guardian in January. “There are officers that have been trained to come here to supplement what we do,” he said.

Byrne said they would backfill and do the lower-risk jobs, freeing PSNI officers for tasks carrying greater risk. “The most likely scenario, should it happen, that would need us to ask for help, would be sustained and multiple sites of disorder where there is an outbreak of violence,” he said.

The chief constable said there was “no evidence” that the rise in frequency of attacks by dissident republicans against the police was driven by the uncertainties and tensions over Brexit.

He said a small number of people were behind the violence: “No one wants to see a return to those dark days, and that is juxtaposed [with] the determination of what is a very small number of people to still use violence as a means to use a political end, and there isn’t a critical mass.”

But he feared the terrorists would manage to kill. He said: “My concern as a chief, when you look at the series of recent attempts to kill or injure our staff is that we have struck lucky, and eventually our luck will run out, and you will have a chief’s nightmare of following a police officer’s coffin to a funeral.”

Byrne said the PSNI must grow urgently after losing 500 frontline staff since 2010, bringing the force down to 6,746 officers. The money for policing announced by the Boris Johnson government does not include Northern Ireland.

“We are stretched and we can’t keep going just by propping up the PSNI with overtime because it is unsustainable,” Byrne said.