TREC (formerly Le Trec, then BHS Trec and from 1st October 2014 it will be Trec GB!) is a 3 phase competitive sport, popular with people who like hacking but want a bit more. The 3 phases are: orienteering on horseback (also called POR); control of paces (or COP, a fast walk, then a slow canter timed over a set distance); and an obstacle phase (also called “PTV”). The obstacles are intended to simulate hindrances you might have to negotiate out hacking and the aim is to have a calm, obedient, manoeuvrable horse/ pony.
Trec competitions are held mainly over the summer months, however there may also be some "Indoor Trec" run over the winter which is only the Obstacles and the Control of Paces sections. A "Full Trec" is as described above, sometimes you may see a "Versatile Trec" competition, where the Orienteering section is replaced with an "Obedience Test", which is like a dressage test but marked only on accuracy, not marked on outline or way of going of the horse or pony. Your aged Arab could go around with a hollow back and his nose in the air and still get full marks if everything is completed accurately and with calm control. In Trec, the judge is looking for a horse that looks like a great hacking partner, not the next great dressage prospect!
Trec is predominantly a ridden sport, although you will find some Fun Trecs which allow the Obstacles and sometimes the Control of Paces to be done In Hand. You may find that the criteria for "good leading" of your equine around the obstacles differs in some areas between Trec and Horse Agility, as there are some differences in schools of thought between the "BHS way" and the "Natural Horsemanship way", with Horse Agility being influenced more by the latter. However, they are not mutually exclusive.
For more about Trec, visit the TREC GB website. For dates of training clinics and local events, see the BHA training calendar and competitions page.