Police are warning householders to be vigilant after a man impersonating a technician made his way into a house in the Harrowby area of Grantham.
The man was driving a white van with red lettering on the side, making it look like a Virgin Media van.
Virgin has confirmed this was not one of their employees.
A Lincolnshire Police spokesman said: “This male has had entry to the property although nothing was taken at this time. Please be vigilant if anyone knocks on your door with the same MO. If you see anything suspicious or anyone attempts to knock on your property, please call 101.”