Detective Sergeant Nick Bailey was the first person to enter the home of Sergei Skripal after the Russian double agent and his daughter Yulia were found poisoned in March 2018, a judge who oversaw a preliminary High Court had heard.
Master David Cook had overseen a preliminary hearing in June 2021 and considered issues relating to the disclosure of information.
A spokesman for Horwich Cohen Coghlan Solicitors, which represents Mr Bailey, said on Tuesday that a settlement been agreed.
He said the details of the settlement were confidential.
Lawyer Patrick Maguire, a partner at Horwich Cohen Coghlan, added in a statement: "We are pleased to reach this settlement with Wiltshire Police which brings this litigation to a conclusion.
"All the issues connected to this case have had a major impact, not just on our client and his family, but the nation as a whole.
"We are grateful for the collaborative approach demonstrated by Wiltshire Police over the past few months which now puts our client and his family in a position to move on with his life.
"Life has never been the same since that day in 2018 for Nick and this feels like a huge step forward in terms of getting some level of closure."
Mr Bailey left Wiltshire Police after 18 years following three attempts to go back to work.
Mr Skripal and his daughter Yulia survived the attack but the incident later claimed the life of Dawn Sturgess, 44, after she came into contact with a perfume bottle believed to have been used in the attack and then discarded.
Her partner, Charlie Rowley, was left seriously ill but recovered.
Two Russian nationals were accused of travelling to the UK to try to murder Mr Skripal with Novichok, smearing the highly toxic substance on the door handle of his home in Salisbury.