Residents are being warned about a potential scam after two bogus officials were reported in Lincolnshire.
The incidents happened in Holbeach St Johns and Whaplode on Tuesday (27 January).
On both occasions, two men dressed in high visibility jackets claimed to be from the council and were offering free loft insulation.
A Lincolnshire police spokesman said: “These types of offence are despicable as the offenders prey on the elderly and vulnerable in our society.
“They try to trick their way in by pretending to be officials. Thankfully, yesterday they were foiled by quick-witted residents.
“Be a good neighbour. Keep an eye on callers to elderly or vulnerable neighbours. If you are suspicious record car registration numbers.”
Anyone with information about the two incidents is asked to call Lincolnshire police on 101.
If a crime is still in progress, residents are advised to call 999.