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PA
A nerve agent attack in Salisbury three months ago cost the police force £7.5m, according to the region's Police and Crime Commissioner (PCC).
Former Russian spy Sergei Skripal and his daughter Yulia were poisoned in the city on 4 March.
PCC Angus Macpherson said Wiltshire Police "came to the fore" with more than 140 officers on duty at the height of the operation.
He described it as a "massive effort" which also involved 40 other UK forces.
Mr Macpherson revealed the financial costing and said the figure could still rise.
He described it as a "national operation which must be paid for nationally".
"I don't want anyone to forget the undertaking of policing minister Nick Hurd when he said [the government] would meet the costs," he said.
Mr Macpherson also thanked the people of Salisbury "for showing their resilience" while investigation and decontamination work was carried out.
Wiltshire Police Chief Constable Kier Pritchard described it as an "unprecedented incident" which saw "the very best of UK policing".
Mr Skripal, 66, and his daughter, 33, were taken to Salisbury District Hospital after coming into contact with the military-grade nerve agent Novichok.
Wiltshire Police Det Sgt Nick Bailey, who was one of the first on the scene, was also admitted to hospital for treatment.
All three have since been discharged.
The UK says Russia was behind the attack but Moscow denies involvement.
The Maltings shopping area was closed to allow extensive decontamination work to be carried out and reopened on 26 May.
Some £250,000 has been given to businesses in the city affected by the aftermath, some of which saw revenues drop by 80%.