But Dr Tom Smith, who teaches international relations at the Royal Air Force College and specialises in terrorism and political violence, did say it was still a shock.
‘Having an attack happen in London is not something you see every day,’ he said.
‘But there is some inevitability about this happening. It has been a case of when rather than if in the light of attacks in Paris, Brussels, Nice and Berlin.’
Dr Smith, who has been employed by the university for two years, added: ‘The fact the attacker targeted parliament is notable. He could have done it in Oxford Street where there’s more people but he chose Westminster. This could be to cause fear.
‘But with the security around parliament and the crash barriers, he got nowhere near it. By doing this, the attack has exposed that the people most at risk are the public and the security forces protecting MPs.
‘The vulnerable people aren’t necessarily the MPs but shoppers, workers and tourists. That will have a knock-on effect and the security forces will have to look at that.’