British efforts to reverse this normalisation of WMD have included participating with the US and France in air strikes in Syria in April, aimed at redrawing some Obama-era ‘red lines’ that were blurred by six years of unpunished chemical attacks by the Assad regime. At the same time Gavin Williamson, the Defence Secretary, has pledged £48 million to build a new chemical weapons defence centre at Porton Down, and elements of de Bretton-Gordon’s disbanded CBRN regiment are being reconstituted. Quietly, this summer, the British Government has also pursued a high-stakes diplomatic gambit to ensure chemical attacks are no longer easy to get away with, by granting the OPCW powers to attribute blame for chemical attacks. Russia has repeatedly blocked such moves, but last month a special session of OPCW member states was convened and despite Russian pressure, 106 members turned up and 82 voted in favour of granting the OPCW powers ‘to identify the perpetrators of the use of chemical weapons’ – initially in Syria alone but then, so Britain hopes, around the world. ‘The taboo against the use of these weapons is breaking down and today the OPCW has not just the power to say the chemical weapons have been used, but can also point the finger at whoever did it,’ the then Foreign Secretary Boris Johnson said afterwards.

If the worst came to the worst, however, and a major attack did unfold, Britain would fall back on the Reserve National Stock, a chain of warehouses filled with antidotes and drugs for use in the event of a catastrophic WMD event. It was established in the 1970s after the eradication of smallpox, when dumps of the smallpox vaccine were maintained just in case the disease re-emerged. In 1995, after sarin terror attacks on the Tokyo subway launched by the Aum Shinrikyo cult, nerve-gas antidotes were added. Following 9/11, countermeasures for anthrax were also included; then, in 2003, the nerve agent response was upgraded with better drugs and personal-protection gear. Critical chemical- and biological- weapon treatments are strategically positioned around the country, with the aim of getting essential supplies to almost any affected location within five hours.

The kind of items in the stock is made clear in an NHS England document, identified with the bland ‘Gateway Reference Number 03088’. ‘1. Nerve agent antidote pod to treat 90 people. 2. Obidoxime further treatment for nerve agent poisoning. 3. Dicobalt edetate pod for treatment of cyanide poisoning in 90 people. 4. Botulinum antitoxin... Antibiotic pods (oral ciprofloxacin) to treat 250 adults for 10 days… with post-exposure prophylaxis for anthrax, plague or tularaemia…’

You get the picture.

The Reserve National Stock is kept under review, to ensure it contains the right kit and drugs to meet current threats. But that also begs a question: will it be able to respond to threats in the future? For no sooner have WMD resurfaced than the nature of the threat they pose is changing.

Today, for example, biological pathogens can be modified to ‘improve’ their lethality using gene-editing techniques such as Crispr-Cas9. Because of their ease of use, these techniques – more usually lauded for their medical applications – have been described by James Clapper, America’s national intelligence director until last year, as weapons of mass destruction, as they do not require a vastly sophisticated lab. ‘It makes it easy for individuals to operate outside a formal institutional setting,’ says James Giordano, professor of neurology and biochemistry at the Pellegrino Center for Clinical Bioethics of Georgetown University Medical Center in Washington, DC. ‘Crispr lends itself to biohacking.’

Biohacking sounds subversive, but in fact is merely the name given to the growing trend for DIY bioengineering, carried out by amateurs with no malicious intent, usually on entirely benign organisms, such as yeast.

Take a turn off the stalls of Shepherds Bush Market in west London, for example, and you will come across 45 purple and pink shipping containers. This is Open Cell, where biotech innovators can rent access to lab equipment like a thermal cycler (to reproduce DNA) for a few hundred pounds a month. Open Cell has the relaxed campus feel common to many collaborative working spaces of which entrepreneurs are fond. Except here, budding young companies are working on encouraging flies to do the pollinating work of bees, say, or exploiting potato waste to make chipboard-like material. It is a sign of London’s thriving biotech start-up scene. But it is also a sign of how biotech is breaking out of the state- or university-run lab. ‘That is exactly our passion,’ says Open Cell’s co-founder, biotechnologist Thomas Meany. He makes plain that security is a top concern, pointing to CCTV on site and constant threat assessments, as well as vetting of potential tenants. ‘We work with organisms you might find in your tummy or on your skin,’ he says. ‘We don’t use anything that could be potentially hazardous.’

Nevertheless, Open Cell is part of what Giordano calls ‘an increasingly global independent DIY movement’ in biotech. ‘It is not a Wild West of biohacking cowboys,’ he says. ‘But the ubiquity of these techniques now means people may drift outside the norm of a community through a “let’s see what happens” spirit. They may not be operating with controls to see something bad coming then mitigate it if it happens. Then of course other groups may simply not care – they want to see if they can do something a bit disruptive. They might say, “Let see if we can build something that will make people sick.”’