British Prime Minister Theresa May has visited Salisbury a year after a nerve-agent attack against a former Russian spy in the English city.
During her March 4 visit, May called the anniversary "an important milestone for Salisbury as it emerges from the shadow cast by the use of chemical weapons."
She also praised the "spirit and resolve" of people in the city.
Russian double agent Sergei Skripal and his daughter, Yulia, were discovered collapsed on a bench in the city on March 4, 2018.
British authorities have determined that they were poisoned by the nerve agent Novichok developed by the Soviet military.
The Skripals survived after weeks in critical condition, but Dawn Sturgess, a woman who the authorities said came in contact with the poison after her boyfriend found a fake perfume bottle containing it, died in July 2018.
British authorities have charged two Russian men identified as agents of Russia's GRU intelligence service with carrying out the poisoning.
Moscow has denied it had any involvement in the poisoning, which led to a series of sanctions against Russia by the West and tit-for-tat diplomatic actions.
The Russian Embassy in London marked the March 4 anniversary by publishing a list of what it said were "unanswered questions" about the poisoning.
It also reiterated Moscow's denial that Russia was the source of the nerve agent, and accused British authorities of "secretiveness and lack of clarity" about the attack.
In a press conference in New York marking the anniversary, Russia's deputy UN ambassador, Dmitry Polyansky, renewed calls for Moscow to have consular access to the Skripals, .
Yulia Skripal declined assistance from the Russian Consulate in London in a statement issued on her behalf by British authorities last year.