On Wednesday afternoon a police officer was stabbed and killed by an assailant outside the British Houses of Parliament.
A car also ploughed into a crowd of people on Westminster bridge, killing one woman and injuring many. Three French teenagers on a school trip to London were also badly injured in the attack.
At present, five are confirmed dead and 40 people have been injured.
The political editor of the Independent, Joe Watts, whose office window overlooks where the attack took place, shared his thoughts on the tragic attack.
Explaining the developing situation via Twitter, Watts commended the security and ambulances services for their work.
Initially, the car striking the crowds of tourists and Westminster workers was a harrowing experience.
Watts explained that the efficiency and professionalism of the security services was second to none.
After being evacuated to a safer location, Watts explained that the atmosphere was slightly strange.
But what was perhaps most striking about his ongoing report, were the actions of the paramedics.
After armed police shot and neutralised the attacker he dropped to the floor immediately.
Then, despite this man attacking them only moments ago, paramedics immediately began treating him for his injuries attempted to save his life.
Watts sent one final tweet reflecting on the two teams.
You can follow all the latest developments in the Westminster attack using the Independent's live page.
Watch: London attack: What you need to know