But events such as these will always raise the question of whether they could have prevented the most recent high-profile terrorist incident, in this case the London Bridge attack, which took place last Friday in ISE ’s host city. Usman Khan killed Jack Merritt and Saskia Jones in a knife attack that began during a prisoner rehabilitation conference at Fishmongers Hall to which he was invited.

Khan was convicted of terrorism offences in 2012 and sentenced to an indeterminate public protection (IPP) sentence, which was reduced on appeal to 16 years. He was released on licence in December last year and ordered to wear an ankle tag. Despite an appeal by Merritt’s father not to politicise his death, the policies that led to his release when evidently not rehabilitated have become a key theme of the debates in the run-up to the UK General Election.

So could any of the low- or high-tech solutions on display at ISE have prevented the London Bridge attacks? Khan’s murderous rampage ended on London Bridge in the shadow of the vehicle barriers that had been erected in response to the 2017 London Bridge attack, when terrorists rammed pedestrians with a van before running through nearby Borough Market stabbing people. Despite being a convicted terrorist in one of the most CCTV-heavy cities in the world, facial recognition and his tag would not have flagged up Khan’s presence as untoward as he had been granted permission to attend the event.

There is the additional problem of security responses always being one step behind the last attack. The attempt by Richard Reid, AKA the Shoe Bomber, to detonate an explosive device on a flight led to the introduction of unwieldy and expensive additional scanning procedures at airports and queues of passengers in socks, despite the attempt never having been replicated. And the vehicle crash barriers installed on London Bridge and outside the Houses of Parliament – the latter installed in response to another 2017 attack – while effective, would only work against the same type of attack in exactly the same location.

If politicians could step away from the blame game, it is parole policy and the surveillance policy governing both suspects convicted terrorists released on licence that would benefit from an overhaul.