Despite Theresa May's positive insistence that Parliament will come together as 'normal', MPs and staff who felt that their life might have been under attack will be feeling anything but normal.
Members of Parliament and other staff were yesterday asked to lie on the floor and locked inside their place of work while police shot dead an attacker who had already killed members of the public and breached the first layer of security, by killing a police officer many of them greeted each morning. Add to that, the death of one of their colleagues, Jo Cox, who was shot and stabbed to death outside her constituency surgery less than a year ago, and MPs and their staff will inevitably be feeling understandably high levels of emotional distress.
"Any event that brings death into sharp focus has the power to make those affected feel fearful for their lives."
Any event that brings death into sharp focus, such as yesterday's attack, has the power to make those affected feel fearful for their lives and potentially traumatised. Of course, MPs have known for some time that there are those out there who would wish them harm and even want to kill them. But understanding this as an abstract concept and experiencing a taste of it first hand are two different things altogether.
As Adrian Bailey, a Labour MP, observed last night while speaking to BBC News: "We go into parliament every day and see warnings about attacks and danger but, like a lot of people, we live with them and don't take much notice but [the attack] was the very uncomfortable realisation that this is for real."
Of course Theresa May is right to insist that: "Parliament will meet as normal. We will come together as normal," not least because the sooner you can empower the victims of a traumatic event to start functioning normally again, the less likely they are to enter into a helpless 'victim' mindset and the less risk there is of them developing long-term psychological damage. But MPs will be feeling anything but normal. They will be deeply aware that people said goodbye to their loved ones, left their homes yesterday and travelled to the same place as them, only to never return.
"As well as showing strength, the leaders of the House of Commons must also show compassion."
Thoughts that this could have been them or might be them in future will naturally preoccupy their mind. This is normal and to be expected. So it's important that as well as showing strength, the leaders of the House of Commons also show compassion by giving MPs the opportunity to talk about what's happened, so that they can process and let go of worrying thoughts, instead of just attempting to plough on as normal as if nothing had happened. At the same time, constantly going over and reliving events, and 'what if' scenarios, isn't healthy either. Those MPs experiencing strong flashbacks, intense anxiety about reentering their place of work and other symptoms of Post Traumatic Stress Disorder may even need specialist trauma counselling.
Sensitive issues that could also impact on the psychological wellbeing of MPs now also need to be considered, such as whether or not to allow a shrine to occur where officer Keith Palmer so bravely lost his life, or put in place a memorial book.
Unfortunately, with 13 terror attacks already thwarted since 2013 and 500 live counter-terror investigations at any one time, yesterday's attack is unlikely to be the last. Parliament remains under the highest levels of security threat.
What matters now is helping MPs to cope with the potentially distressing risks they expose themselves on a daily basis, by showing them our compassion and support and also encouraging a less divisive form of politics. The more interconnected and supported MPs feel during a normal working day, the more likely they are to support each other after a crisis and the less likely they are to suffer psychological damage, so that they can carry on the important work of government in the aftermath of a human tragedy.