I'm not trying to freak anyone but in today's world, electronic surveillance is increasing. It's carried out by all sorts of government bodies let alone for criminal activities. GCHQ is a minor worry in the grand scheme of things, there's the D.S.S., Customs, Plod, Secret Service, newspapers, private investigations, insurance claims departments, the list goes on.
So here are a few pointers just in case you are a "person of interest" and didn't know it.
Things to look out for on a telephone.
Static, crackling, interference, echo, or just general fluctuations in the quality of your telephone.
Clicking on the line.
Finishing a call then quickly raising the handset finds the line still held on.
Callers reporting that you're sometimes on the phone when you weren't.
Callers having difficulty hearing you, they hear echo, clicking, etc.
Dialling sometimes needs to be repeated.
Busy answering machines may suddenly be empty.
Your phone company does work on your telegraph pole or arrives to clear a phone fault you knew nothing about or to 'upgrade' your phone line.
Wireless Devices (Bugs)
Sudden continuous or intermittent interference to your TV, radio, Hi-Fi, or wireless communications.
Your wireless baby alarm starts to crackle or whistle for no reason.
Using a portable radio, carefully scroll through the full spectrum of the FM radio band.
If you hear a squealing noise, it could be feedback caused by a bug nearby.
Keep the radio on this frequency and move it around the room to detect the location of the bug.
The feedback volume increases as the radio nears the bug.
Spy ware might be on your cell phone if:
The screen lights up for no reason
The flash on the camera goes off when you're not taking a picture
You notice ambient noise in the background when you're on a phone call
You repeatedly get strange text messages from an unknown origin
Texts don't arrive.
Your phone starts polling a lot, some phones have a LED that flashes when this happens or if they are alongside a radio, you'll hear a digital burst.
It's difficult to hold a conversation or to get a line.
Your phone battery runs out faster.
Your call log doesn't match up with your own log of events.
Your phone bill shows the occasional call you know nothing about.
CAUTION:- Just changing your SIM card won't get rid of any tracking or remote access software. If you are doing something you don't want monitored or your location tracked, take the battery out of the phone.
Internet Surveillance
Your Internet starts running slowly.
There is unexplained hard drive activity.
Your hard drive starts to fill despite you not adding anything to it.
Files appear you cannot access.
Files disappear,
Every so often the waste bin is found restored or emptied.
Your firewall or virus checker reports intrusions or even worse you find it turned off.
Your system settings change. Remote access is found enabled.
Your router shows the presence of an unknown station or activity when nothing is switched on.
You receive an email with an attachment that doesn't open when you try to run it or you get an unsolicited free software demo program or gift.
Caution, you may be tempted to open email attachments from people you know and trust. Only how do you know it was them that sent the message? Always check before opening attachments.
Physical Signs
Be wary of break ins where little is stolen.
Doors or windows may be found unlocked when you were certain they were secure.
A neighbour reports activity when you were out.
Electrical sockets, wall plates or fixtures and fittings seem to have been moved or are not straight when no work has been undertaken.
Damaged or disturbed ceiling tiles, or debris is discovered on surfaces could indicate unauthorized entry into the false ceiling or tampering.
Disturbance to furniture, office equipment, ornaments or drawers and no explanation for this can be found.
New or newer items (radios, clocks, phones, power adapter, lamp, calculator etc.) suddenly appear in your office or home with no hint of how they got there.
Finger prints appear in dust where it is largely inaccessible.
Newer light bulbs are found, glass smeared on mirrors. the dust is disturbed on light fittings.
BOLO for unusual or unscheduled people or vehicles.
Extra cars in the road, contractors vehicles, often vans, are parked near to your home or office building for extended periods of time.
You notice the vehicles have extra aerials or 'stubs'.
People sitting in vehicles for long periods.
You cannot clearly see the person in the vehicle even from a close range.
Unscheduled workmen turn up to perform maintenance work on the air conditioning, plumbing, electrics, telephone cabling etc.
As said, I'm not trying to freak folk, just list a few common examples of how electronic surveillance can be recognized.