My paranoia levels have increased dramatically since I read a confidential Defence Force security manual, carelessly left on my city bus seat.
The manual's first chapter is called "Basic Principles of Defence Security".
It appears to lump certain journalists into the same classification as fanatics who wear suicide belts packed with explosives.
Subversion, it darkly suggests, is action designed to "weaken the military, economic or political strength of a nation by undermining the morale, loyalty or reliability of its citizens".
In the case of journalists, one assumes this refers to dumbing down the intelligence levels of the nation by feeding everybody a continuous diet of frivolous froth about so-called celebrities.
I've long suspected that I've been under surveillance, ever since the Security Intelligence Service began buying my original cartoons some years ago.
I foolishly believed this was because its staff shared my warped sense of humour. But after reading documents released by US intelligence whistleblower Edward Snowden, I realise they wanted my work for more sinister reasons.
Otherwise, why insist that I simply mail the cartoons, rather than using normal undercover communication procedures, such as discreetly exchanging documents and money in identical briefcases at a drop-off point?
They clearly wanted me to lick a postage stamp, to secure my DNA.
Thanks to Snowden's revelations, I recently took the precaution of upgrading my mobile, and to confuse the spooks I've left my GPS position running on the old phone.
Discreetly concealed in a weatherproof plastic bag, the device is now being continuously recharged by the perimeter electric fence at the GCSB's communication station at Waihopai, near Blenheim.
If you call the number you're greeted with a message, quoting Baroness Orczy's famous line from The Scarlet Pimpernel, "We seek him here, we seek him there ..."
Unfortunately, despite my vigilance, I suspect I may yet again be under security observation at my latest rural hideaway.
The property has recently been invaded by countless cicadas. Well, most people would presume they are cicadas, but we paranoiacs known better.
Clearly these are the latest electronic eavesdropping drones, masquerading as insects.
I even found one perched on my computer, presumably extracting the contents of my hard drive.
I've had extensive discussions with my psychiatrist about my latest anxieties and suspicions and he agrees with me - it's a bit of a worry.