The UK defence secretary has warned the world could face more chemical attacks, speaking ahead of the third anniversary of the Salisbury poisonings.
Former Russian double agent Sergei Skripal and his daughter Yulia were targeted in Salisbury with Novichok nerve agent in March 2018.
Later that year, resident Dawn Sturgess died after touching the substance.
Ben Wallace said he was worried about those who have "disregard" for international law.
"We can't take anything for granted in the way we maybe did in the Cold War when there was a nice, static and fairly sterile relationship with a fence down the middle of Europe," Mr Wallace said.
"What I worry about is when people have disregard for the international rule of law and domestic rule of law and those people are no longer purely terrorists/organised criminals but other states.
"It challenges many of the values we stand for and it challenges the world order. That is something that should worry us all."
Ms Sturgess came into contact with the military-grade nerve agent, developed by the Soviet Union in the Cold War, after handling a perfume bottle which was found by her boyfriend Charlie Rowley.
It is thought the Skripals came into contact with it after it was left on their front door handle.
A UK investigation blamed Russian agents for the Novichok attack, identifying two suspects using the names Alexander Petrov and Ruslan Boshirov.
Both deny any involvement but are wanted by UK police after charges were authorised against them.
In total, six people came into contact with the nerve agent in Salisbury. Only Ms Sturgess died.
A pre-inquest review into Ms Sturgess' death is due to take place at the end of March.
Tracy Daszkiewicz was Wiltshire Council's director of public health when the Skripals were found slumped on a park bench, in the centre of Salisbury, foaming at the mouth.
Ms Daszkiewicz now works for Public Health England.
She said she was wholly unprepared for the death of Ms Sturgess a few months later.
She said: "I remember getting the phone call and us regrouping… I can't even describe it, just absolute disbelief, [that it had happened again] total disbelief, and that whole realisation that you're almost starting again.
"Nobody had dealt with anything like this."
"The most awful part of all of it was when we knew how poorly Dawn was. Losing Dawn was absolutely devastating," Ms Daszkiewicz said.