Obsessive CANTER Disorder

My horse has developed a new habit!

I was asking for a trot and he trotted a few steps and took off into a canter. At first I just let him go, he hasn't been rode in about a week due to my work and the weathers time for spunk! Well I asked for a trot, then a walk he did fine. So I walked a lap around the arena and asked for the trot again. He bobbed his head and quickened his pace like he was going into the canter, but didn't; all of a sudden he took off again. I sat deep into my saddle and pulled back and he just fought the bit! This happened each time I asked for a trot! I think it might have been a mistake just to let him take off into a canter because now he doesn't want to stop! When I tried to slow him down he gave a buck, not big but he wanted to take off!

Want can I do to break this habit if it becomes an everytime thing!

It definitely was not a good idea to let him get his way at the beginning of your ride. A better way to handle that would of been to rein him in, ask him to trot nicely atleast a few strides, then ask HIM for a canter. Since the damage is already done though, you might want to try some trot to canter transitions on both leads and make sure he's paying attention to you. Make him keep doing it until he's trotted as soon as you ask him to transition, and to pick up a nice EVEN canter (no crazy running with the head up, back arched, etc) when asked. You can try telling him to trot at different paces also. (a working trot, extended, etc) without letting him evade your cues or get ahead of you (break into the wrong gait, etc)

Thanks! I realize now that it was definitely a mistake on my part!

First of all, it would be a bad idea to use both reins pulling back on him and if he is already resisting the bit then it will only get worse if you do that. You need to learn and practice the one rein stop. The other thing you could do is let him canter and keep cantering until he wants to stop and then ask him to keep cantering another lap until he is tired. Soon he'll not want to do that anymore.

What are you like as a rider? Brave?
You can go two ways about a problem like this - which, by the way, is not 'obsessive' and set in stone, if it was only one ride and he's been out of work for a little while he's probably just feeling a bit full of himself.
You can go for the above option, of bringing him back and not letting him canter until he settles in trot, or, if you're gutsy enough to do it, LET him canter but drive him as hard as you can, so that he is having to work twice as hard as if he was trotting. Drive him around the circle for a few laps, then ask him to come back to trot. If he doesn't respond immediately, drive him back up again.

Some horses use canter as an evasion when the trot work starts getting hard. My gelding used to do it as an evasion in trot as soon as I'd start picking up some contact and asking him to come through the rein. He'd go ' well that's a bit hard' and canter instead. So I'd drive him on, make him get a bit of a puff going, then ask him to trot. The first time it took me 5 canters to get him to stop using it as an evasion. After that, as soon as he went to canter as an evasion, I'd put my leg on, canter a few strides, come back to trot and he'd be fine.
He has not done it for over a month now, he'll think about it, do one stride, and then go back to a good trot.