I didn't directly witness the horrific attack in Westminster this week, but it is a near miracle that I didn't.
My office is on the 5th floor of Portcullis House, the modern building that directly overlooks the place where the attacker crashed his car into the railings of the House of Commons, and New Palace Yard where he fatally stabbed a Police Officer and was then shot dead.
Literally seconds before the attack the Division Bell rang to call MPs to vote, and I left my office to take the lift to the ground floor, and walk through the tunnel under the road where unbeknownst to us the attack was unfolding overhead.
I emerged into the New Palace Yard seconds before the shots were fired, but then entered the Commons building to go to vote and did not hear the gunfire. Moments later however as I walked into the voting lobbies we were told that an incident was ongoing and to remain where we were.
Some colleagues arrived and reported that they had seen what had happened, a Police Officer under attack and the assailant shot just a few yards from where I had just been walking.
We remained on lock down in the House of Commons chamber and the surrounding lobbies for the next four hours, as news seeped in about the other aspects of the attack, and the carnage on Westminster Bridge. The atmosphere was one of resolute calm, and sadness as we learned of the deaths and injuries outside.
PC Keith Palmer was one of the officers I pass and say good morning to everyday as I enter the gates of Parliament and use my pass to access the estate. He was one of the unarmed officers who check passes and give directions to the many tourists who visit Westminster and wander up to have their photos taken with Big Ben in the background. He gave his life bravely defending democracy.
Since 9/11 there are many more armed officers standing nearby ready to deal with any serious threat. Sadly PC Palmer was fatally stabbed before those officers were able to shoot his attacker. There will be a full enquiry into how the stabbing happened, but it is hard to see how you can stop a person with murderous intent driving a vehicle into innocent pedestrians.
Sadly it is an experience which occurred in 2012 in my constituency of Cardiff West when a mentally ill individual drove a vehicle at pedestrians, killing my constituent Katrina Menzies and seriously injuring several others.
You can put up barriers around obvious targets like Parliament, but unless you have advance intelligence, you cannot prevent a deranged and crazed individual from driving at a crowd of pedestrians.
Of course it wasn't just MPs caught up in the lockdown. Thousands work on and around the Parliamentary estate, and Wednesday is the busiest day for visitors due to Prime Minister's Questions. Amongst those on lockdown for hours were several school parties. As a former teacher I could not help but think of the teachers with the French children who came under attack, but also of the teachers on the parliamentary estate with very young children who acted professionally to the youngsters in their care throughout.
The sad truth is this is not the first attack in Westminster, London or the UK as a whole, and it will not be the last.
During the Second World War Hitler's Luftwaffe destroyed the Commons chamber, but MPs carried on meeting in the Lords. It was rebuilt but Churchill and Attlee agreed to incorporate the broken archway at the entrance of the Commons chamber as a reminder. In the 70s an IRA bomb went off in Westminster Hall, and in 1979 - Airey Neave MP was murdered yards from Wednesday's attack by an INLA car bomb.
In July 1990 in East Sussex, Ian Gow MP, was killed by an IRA car bomb, and of course last year Jo Cox MP was murdered in her constituency by a right wing extremist. I was in Westminster in July 7th, 2005 when bombs went off across London in the 7/7 attacks. No doubt we will face future attacks too.
But on Thursday at 9.30am the Commons met as usual. We observed a minute's silence and got on with our normal business.
Democracy is frustrating and imperfect, but it is a stronger idea than terrorist violence, and the democratic thing to do in the face of terrorism is to keep calm and carry on.