Royal Mail is investigating fake stamps bearing Diane Abbott's face that have apparently been making their way around the postal network.
Photographs of the stamps - one postmarked and another that has yet to be franked - have been shared with the Gazette by someone claiming to be a postal worker.
The anonymous postie said they had spotted the stamps featuring the Hackney North and Stoke Newington MP in the system and believes they could be a "lighthearted stunt".
Nevertheless, faking stamps is a serious offence, and the Royal Mail is looking into the matter.
The worker told the Gazette: "I have spotted what apparently nobody else has... there's a Diane Abbott stamp making it through the mail.
"Obviously it's a serious offence to send fraudulent stamps through the mail, though I feel this might be a lighthearted stunt."
A Royal Mail spokesperson was less forgiving, telling the Gazette: "It is a crime to create or use counterfeit stamps. Royal Mail takes the necessary steps to protect stamp revenues which help fund the universal postal service which serves the UK's 30million households and businesses.
"We will seek to prosecute where we find someone has created counterfeit stamps or knowingly sold used stamps for re-use. This matter is being investigated by our security team."
Ms Abbott has been contacted for comment.