THE days when any public event or celebration were free from the threat of Islamist inspired terrorism seem like something from the distant past. With the current UK terror threat level set at severe, it’s perhaps no surprise that this year’s armed police presence during Edinburgh’s Hogmanay celebrations will be much more visible.

“This year I will be deploying armed officers overtly, and the public should be aware of that but not alarmed,” Edinburgh’s Chief Superintendent, Kenny Macdonald, pointed out this week, stressing that the police response remains appropriate to the event.

Visitor numbers alone for the capital’s famous street party are already up on last year. Between Christmas Day and 31 December a rise of 5,000 passengers was expected to have arrived into Edinburgh Airport, continuing the upward trend of recent years.

Any increase in numbers is to be welcomed, but with it too comes the need for tighter security given the obvious vulnerability of such mass public events. Not only will road, rail and air routes into the city undergo extra scrutiny but on the streets anti-vehicle barriers and other cordons are already in place.

That the threat from Islamist inspired cells or individuals, so-called “lone wolves”, remains a real and present danger, was brought home again with the recent arrest of four men in South Yorkshire and Derbyshire who may have been hatching an alleged Christmas or New Year terror plot.

As of yet there is no proof that any of the men involved were terrorists. But the nature of the police operation using a bomb disposal team when raiding one of the suspect’s premises suggests that intelligence or intercepted communications indicate something security officers needed to get to the bottom off.

The whole issue of the current threat posed in the UK and Europe by jihadis returning from the battlefields of Syria and Iraq as the Islamic State (IS) group finds itself routed from stronghold cities like Mosul and Raqqa, has been the subject of speculation for some time. But as the recent Intelligence and Security Committee’s annual report to the UK Government revealed, more than 300 UK nationals who fought for IS were likely to return soon to the UK and may well be primed to carry out attacks. One MI5 officer summed up the uncertainty: “I am very concerned about it … a year from now most of them will not be in Syria and Iraq, probably. Who can say how this will unfold?”

The UK’s security services say the country had now recorded the largest ever surge in “high risk” terrorist suspects and the threat was growing at the fastest ever rate. In all MI5 has about 3,000 “subjects of interest” on its watch list and a larger group of 20,000 suspects who are monitored because of their involvement in previous investigations. This should be a cause for concern on a number of levels, not least given that the security services themselves also recently admitted that they missed three opportunities to identify Salman Abedi as a possible terror suspect in the run-up to his suicide bombing at an Ariana Grande concert in Manchester earlier this year. Abedi – who was not under investigation – left 22 people dead, including a Scots teenager.

With IS in its latest propaganda video calling on lone wolves to target Christmas and New Years Eve celebrations in western countries and “hunt down” non-believers during the festive holidays there is no room for complacency. As Scottish police are keen point out there is no specific intelligence regarding a threat to the Edinburgh event but vigilance is paramount. These days the barriers and steel gates along with the deployment of armed officers at such public gatherings is an unfortunate fact of modern life. Most revellers though will feel reassured by them nonetheless.