Ali's parents fled the civil war in Somalia.
His father, Harbi Ali Kullane, was a former senior adviser to the Prime Minister of Somalia who came to London in the 1990s to escape the civil war.
It’s believed Harbi Ali Kullane had been targeted by Islamist extremists and even received death threats in the past.
No surprise, then, that he told a tabloid newspaper he was “traumatised” by the actions of his son.
Ali Harbi Ali’s road to radicalisation took place over time and in secret. At one point, his academic career looked very promising.
At secondary school in South London, Ali excelled, but in 2011, when he was 15, the Syrian Civil War broke out and this was to have a profound effect on him.
Ali Harbi Ali
PA
He opted to stay on for A-Levels. His intention was to study medicine at University.
But when he started sixth form the following year, his school work and attendance declined. His A-level results were poor.
The war in Syria was proving too much of a distraction and in 2014 Ali began to watch ISIS propaganda online. His route to radicalisation was well under way.
Ali Harbi Kullane: father of Ali Harbi Ali
PA
It’s known that later in 2014, he voluntarily accepted a referral to the Government’s Prevent programme, designed to de-radicalise extremists.
He completed the process and ultimately was not deemed to be a security threat.
The following year he bought the foot-long knife which he would ultimately use to kill Sir David Amess.
It coincided with MPs voting to join coalition airstrikes against ISIS targets in Syria.
At that point, Ali’s murderous plans were at a very early stage. And a few months later he signed up to a radiotherapy degree at City University in London. Records show he withdrew from the course late in 2016 for "personal reasons".
He now had more time to become immersed in ISIS propaganda. And in 2019 he hatched a plan to attack MPs and the Houses of Parliament in what he saw as “revenge” for the airstrikes in Syria.
He routinely carried out reconnaissance trips including staking out the constituency office of North London Tory MP Mike Freer and the home address of cabinet minister Michael Gove.
But ultimately he settled on Sir David Amess because he was a soft target. In his words: “The easiest to get to."
After the murder of Sir David he told police: "I've done it because of Syria. I've done it because of the innocent people. I've done it because of the bombing. He deserved to die."
Ali Harbi Ali’s journey to radicalisation was complete.