A public inquiry is to begin later in Salisbury, to examine how a woman from Wiltshire was killed by a 2018 poisoning blamed on Russian agents.
Dawn Sturgess, 44, died after coming into contact with Novichok – the same chemical weapon used to target a former Russian spy four months earlier.
The nerve agent had been hidden inside a designer perfume bottle.
The inquiry will examine the circumstances leading to her death, try to establish where responsibility lies and highlight any lessons.
The first week of evidence will be heard at the Guildhall in Salisbury.
Monday’s session will begin at 11:00 BST with a day of opening statements.
On Tuesday, the inquiry will hear about Ms Sturgess from her mother, Caroline Sturgess.
The rest of the week will focus on evidence and experiences from the local first responders, including paramedics and Wiltshire Police.
After a week’s break, the inquiry will move to central London where it will hear details relating to the targeting of Sergei and Yulia Skripal, the former Russian spy and his daughter, who had been poisoned with Novichok in Salisbury in March 2018.
It will also hear about Operation Verbasco, the police investigation into the Novichok incident.
Due to national security, the public feed of the hearings will be on a short delay – and some evidence will be heard in private.
The UK authorities blame the Russian state for the use of the chemical weapon, believing Russian agents were behind the original incident and then discarded the perfume bottle.
It was later found by Ms Sturgess’s partner Charlie Rowley – both thought it was designer perfume.
Mr Rowley was taken ill at the same time as Ms Sturgess, but he later recovered.
Russia has consistently denied any involvement and the Russian embassy has described the public inquiry as a “circus”.
Public hearings are due to conclude in the first week of December, before a final report is published in 2025.