Angus McDonagh has been sidestepping postage costs for years by creating some 50 fake stamp designs and using them to send letters all over the world.
McDonagh, 64, began his personal freepost system three years ago and has duped Royal Mail hundreds of times since.
> A self-styled 'anarchist philatelist', McDonagh started faking stamps in protest at bland stamp design. And his designs are certainly far from dull.
Many feature his own face in the Queen's traditional side profile complete with a comic eye patch or weird hat, while others show family photos such as a portrait of him and partner Jo Purvis, 52.
McDonagh told the Daily Telegraph: "When I started I wanted them to be deliberately silly, so I had a fake moustache or beard or eye patch, that was very obviously drawn on very crudely. "I started it as a bit of a protest. It seemed as if stamps were disappearing due to everyone going online all the time.
"The Queen's head, it seemed to me, was going to disappear from stamps and be replaced with lots of other images and I felt I had to act.
"I just kept going and it has become more and more farcical. It's gone undetected for so long now it is just silly."
But unlike the many people who have cheated the Post Office out of money in the past using "washed" stamps with the postage marks removed, or the eBay traders who have sold fake stamps to collectors, McDonagh insists that his aim was never financial.
"I have never intended to defraud the Post Office," he added. "My solicitor has sent a few cheques for around £200 with a letter saying it is for unpaid postage, but they are always returned."
Nevertheless, he has successfully sent over 100 letters to France, Hong Kong, Australia, Canada and Italy - as well as all over the UK - and only one has ever been detected as a counterfeit. Royal Mail is now investigating the case as a result.