My journey in Thailand will offer you a new season of articles, after the 2008 London one. Please, be patient for the philatelic part, the generalist part will certainly arrive sooner and in full length on the gemini blog of Sebphilately.
In the Machin series news, the Royal Mail reinforced the security printing features. On 17 February, were issued the first postage stamps to fight the reuse of uncancelled used stamps: iridescent ink (already seen on the high value stamps), supermarket price tag's slits, no more water-soluble layer to separate the stamp from the envelope and the adhesive.
Ian Billings, a stamp dealer specialised in British new issues, has been following the case from the first Royal Mail announcement and kept regularly informed the Virtual Stamp Club's readers. I advice you to read his website's pages about these issues (17 février, 31 mars). The latter is about the new stamps needed because of the 2009 change of postal rates.
The main consequences for collectors is the impossibility to remove the stamps from the cover: either they finished torn by the slits or sticky... or both. Billings already discovered that some 2009 Christmas stamps were already without the water-soluble layer.
Many problems for the collectors to correct the incapacity of the postal operator to cancel stamps: sorting machines made for standardized covers, packets franked with stamps uncancelled because the post offices and the postal counter in shop-market-etc are less and less furnished with datestamps, no solution put in the sorting mail centers. Security printing seemed to be easier than to change methods (surely less expensive in human ressources too).
To measure the efficiency of this politic, follow eBay auctions: will there be less auctions proposed with hundreds of British stamps like new but without gum or adhesive?