The Fédération Internationale de Philatélie has published a few lists describing abusive and illegal issues. These stamps were prohibited at FIP exhibitions.
Because these lists became to difficult to manage, it was decided to let the Federations to inform their members.
The following list is the last published in November 1967
Here is the list of all circulars issued by the UPU for the years 1996 – 2003
1996: 2 countries reported
1997: 6 countries reported
1998: 7 countries reported
1999: 6 countries reported
2000: 12 countries reported
2001: 15 countries reported
2002 : 6 countries reported
2003: 8 countries reported
From 2004 the information is on the UPU WNS site.
A presentation in French was made at Paris, Planète Timbres on this topic:
Please download the following presentation and share it with all your friends:
Ms Maria Libera (Wolrdwide Philatelic Observation Unit) has made a very informative presentation that outline the issue of ILLEGAL stamps to the Southern Africa Postal Operators Association (SAPOA) in Pretoria, South Africa, on October 6-7, 2014. Here is a copy of the slides presented.
Here is another presentation on illegals made in Tunis in 2010.
New articles and presentations made by the Worldwide Philatelic Observatory
The editor of Sports Philately Mr. Norman Jacobs has written an article on the subject.
Presentation made on Illegal and Abusive issues by Victor Manta
Presentation made at Taipei 2016