pls help im desperate!!

When I get on my pony, if no one is holding onto him as soon as I sit on him he tried to bolt of. And he is worrying me, because he does it anywhere even on an enclosed yard.
Any suggestions, I will try anything

Are you sure you don't kick him (accidently, of course) when you get on? Any health issues with back or something? Did he do it before or just started recently for no reason?

I'd recommend to keep using helper for a while. Ask not to hold reins, but hold the long lead rope. So pony is "kinda free", but the helper still can stop him if he bolts. So pony will figure out that he'll be stopped in any case.

Val asks good questions...I'd want to know the details before I offered you any advice.

Have you tried lateral bending? Bend his nose around all the way to his side, then mount up. When he is calm and he gives to the pressure, release him.

Let me know if it helped! :)

I agree with kitten-Val - you need to make sure there's nothing wrong and there's no pain causing the problem before you try to find ways to stop it.
The 'lateral bending' technique is a method of getting a horse to submit using an endorphin release (shown to be similar to that used by predators to birng down an animal) and can often be used to cover up a problem instead of addressing what is really going on. Get a vet/equine dentist/saddler out.
If nothing's wrong, I'd suggest going back to basics with him. How old is he? Is it an option to 'rebreak' him in order to sort out these issues? If he's purely being naughty, the best solution might be to simply use someone on the ground and then move on to just you and the reins, to MAKE him stand until you say so.

Sorry, but I cannot stand this method! There are a few videos of it on Youtube and I think it is one of the most horrible ways you can deal with a horse! Sorry to rant, just my opinion!

I would get him checked over for pain, teeth/tack/back etc, then if all is well, go back to basics, do some groundwork with him, and maybe get the handler to hold him, but make him stand when you get on, don't ride off immediately, then when he does stand, give him lots of praise. Like kitten_val said, make sure you don't accidently kick him as you mount and try and sit down as quietly as you can :) Really hope this helps x x x