Does the presence of armed police reassure people?
As two policemen with guns were photographed smiling for the camera at a Christmas market in Newcastle, BBC News questions whether armed officers on the streets reassure people, or make them feel less safe.
We have been used to seeing firearms officers in airports, but now they can be spotted patrolling the streets and locations such as shopping centres - and even outside Canterbury Cathedral.
And when Northumbria Police posted images on social media of the two armed officers, people commented in their thousands.
Many objected to the sight of their "big guns", especially in a festive and family setting.
Northumbria Police said the officers were there to protect and reassure the public.
But sociologist Frank Furedi said there was a risk it could have the opposite effect.
He said: "It very much depends on context, but the idea that this should be a routine way of reassuring the public is fundamentally flawed."
Public opinion expressed on Facebook and Twitter was polarised, with critical comments tending to dominate.
"Shame on you Northumbria Police. Guns should not be normalised. Ever."
"The only message this sends is fear... Its ok kids, we're here to put the fear of god into you as there might be a terrorist on the loose."
"Nothing says Merry Christmas like machine guns in crowded public areas."
Others were more supportive:
"Well done, nice to see that you are out there protecting people.
"People need to get a grip!! When will the public realise that sadly this is a sign of our times."
Northumbria was one of nine forces in England and Wales to be given Home Office funding to increase the number of trained firearms officers.
Det Supt Steve Neill said: "These officers are there to protect people from what is a changing threat.
"The threat level remains severe - there's no specific intelligence that Newcastle or anywhere in our force area is going to be targeted, but we need to be alive to that threat and need to be strong."
He said that the comments on social media demonstrated the "polarised opinion".
"We recognise those concerns, but we are not trying to normalise guns, or officers carrying guns.
"The percentage of armed officers is very small compared to the officers that don't carry weapons, and whilst people are used to seeing them at places like airports, we need to recognise that the nature of terrorist attacks has changed and our police and tactics have changed in response to that."
However, Frank Furedi, emeritus professor of sociology at the University of Kent, said: "If there has just been a major terrorist attack people feel insecure and anxious.
"Sometimes having armed officers on the streets makes people feel more safe.
"However, if it gets routine, as it is in, say, Belgium, people can become more wary - feel they are always under threat, and it has the opposite effect.
"If there is a good operational reason, such as response to a threat, then that is different to simply managing perceptions.
"It you're just doing that then the presence of armed police risks undermining credibility and making people more insecure and anxious."
Dr Sharon Coen, senior lecturer in media psychology at the University of Salford, said: "Research shows that the presence of an armed officer at a large event where there is already a state of tension actually makes it likely for the situation to escalate more quickly and for people to behave violently if things go wrong."
Steve White, chair of the Police Federation of England and Wales, said: "We police by consent in the UK, through proactive and effective community engagement.
"This should not and does not change because of the tools officers carry, firearms included.
"The public understand the very real threat to our way of life from terrorism.
"This threat changes how policing is delivered and, armed or otherwise, a uniformed presence aims to reassure people that their police are there to keep them safe."