"We can now confirm that there is no concern for either his health or any wider risk to the public", police added.
In the British city of Salisbury, another incident occurred near Zizzi restaurant, where in March he was poisoned Sergey and Yulia Skrypali. Investigations are still ongoing.
"There was a very heavy police presence there along with the fire service and ambulances".
Police on high alert have responded to a fresh incident in Salisbury, after a man in his 30s was found in the street near the same venue visited by Sergei and Yulia Skripal.
"Currently, we are dealing with the incident in castle street, Salisbury, with the participation of a person under the age of 30 years", affirmed the police Wiltshire.
"We are now dealing with an incident in Castle Street, Salisbury, involving a man in his 30s", the statement said.
"At the moment there is nothing to suggest any wider risk to the public".
Mr Macpherson referenced major events - the visit by US President Donald Trump and the Royal International Air Tattoo - and continuing incidents in Salisbury and Amesbury as contributing factors, saying a "different approach" needed exploring.
The police, who were called to the scene at 6.20pm on Thursday, said the man has been taken to Salisbury District Hospital and fully assessed by medical staff.
Members of the emergency services had been seen putting on protective clothing.
Charlie Rowley, 45, and his partner, Dawn Sturgess, 44, were rushed to hospital after collapsing in Amesbury on June 29. Sturgess died in a hospital on Sunday.
The Skripals ate at the restaurant shortly before they were found unconscious on a nearby bench on March 4 after being poisoned with Novichok.