Lee Martin said he noticed the flag, which measured “about 10m long and 7m deep” while he was working in the area, the BBC reported.
“It’s disrespectful and it’s antagonising the community after the Novichok attack last year, and with the anniversary that’s coming up on 4th March,” he said.
Glen said he was “thankful” the flag had been taken down swiftly.
“What a stupid stunt – mocking the serious events sadly experienced in Salisbury last year,” he said.
Wiltshire Police said they are examining CCTV footage, but said it was too early to say whether an offence had been committed.
The UK government said two officers working for Russia’s military intelligence service – identified as Anatoliy Chepiga and Alexander Mishkin – carried out the Salisbury attack against the Skripals.