http://www.radal.co.uk/index.html

Now this is a brilliant idea!

Doesn't stop them being pinched though...

No but at least it lets you know where to find them.

The only problem I can see is that, OK - it has a tamper alert so it alerts you when the headcollar with the transmitter has been removed; but once thieves cotton onto this they'll simply remove the headcollar in situ and replace with one of their own. 

Unless you're very close to the horse you may be aware it's headcollar has been removed, but you wont get there in time to stop it being taken.  Then you're back to square one not knowing where it is.....

I also never, ever turn out in headcollars...

Me neither, particularly after one of my horses was slashed across the neck in his field - this was during that spate of horse stabbings/slashings about 12 years ago.  They missed his jugular by millimeters, we could actually see it before the vet arrived to sew him back up.

If he'd had a headcollar on, whoever did it would have been able to get a good hold on him and may have managed to finish the job.

The thought of the headcollar getting caught on something as well - doesn't bear thinking about.

Yeah I did wonder about wearing a headcollar in the field because I was thinking you need a headcollar that breaks free if the horse gets stuck but that defeats the object here. Thats why i think a microchip style idea would work better and be much safer! :)

I don't like any headcollars - makes it too easy for theives and evil people.

Microchips are in development at the moment - the problem is in getting the technology small enough to go in a chip under the skin - and how to keep the batteries charged!