Prime Minister Theresa May announced the threat level increase from ‘severe’ to ‘critical’ in the wake of Monday’s bombing of US star Ariana Grande’s concert which killed 22 people.
The level means that attacks may be expected imminently after Monday evening’s attack on Manchester’s MEN Arena.
She announced that Operation Temperer would start immediately.
It has already emerged that Saturday’s Scottish Cup Final between Celtic and Aberdeen will see increased security.
Today, armed officers were at some of Scotland’s busiest train stations. Police officers were seen with guns at Glasgow Central, Queen Street and Edinburgh’s Haymarket Stations.
David Lister, ScotRail Alliance Safety Director said: “Following the terrorist attack in Manchester, the UK’s security threat level has been raised to critical.
“As a result of this, you will see more police than normal patrolling our stations. At some of our stations, some of these officers will be armed.
“The police are here to keep us all safe and to allow us to go about our daily business,” he added.
“You may also see more of our staff out and about in our stations. Again, they are there to help. If you have any questions, please do ask us.
“Everyone at the ScotRail Alliance’s thoughts are with the friends and families of those people who were caught up in this terrible incident.”
It has also been revealed that the organisers of this Sunday’s Edinburgh Marathon are in talks with Police Scotland about increasing security for the event.
As of yet, there have been no sightings of soldiers in Scotland, with Glasgow Airport confirming that they will not be expecting any.
A spokesman for the airport said: “We continue to operate at a heightened level of security.
“As was confirmed by Police Scotland, armed officers will remain visible and on patrol at transport hubs including the airport.”
It comes as Police Scotland Chief Constable Phil Gormley released a statement confirming the increased threat level.
He said: “My thoughts and those of everyone at Police Scotland continue to be with those who have lost loved ones or who were injured in the attack in Manchester.
“With the threat level now at ‘critical’, we have now established a multi-agency co-ordination centre to lead and co-ordinate the response across the country along with key partners.
“Police Scotland will be increasing our operations to protect the people of Scotland, our businesses and public places.
“This may include a range of options aimed at increasing security at these sites, reassuring residents, businesses, workers and visitors so they can go about their daily lives as normally as possible.
“We increased the number of armed police on patrol at key locations and the public should expect to see armed officers on foot patrol.
“We are reviewing all significant events along with event organisers taking place within the next 14 days,” he added.
“We will increase the security footprint around those events where it is deemed appropriate.
“We have well-rehearsed plans to respond to major incidents and we will be continuing to work with our partners to address the current heightened threat.
“However, there is no intelligence to suggest there is any specific threat to Scotland but I would ask the public to remain alert and report anything suspicious.”