If the horse has been turned out in a large field and you are unable to catch him, the last thing you must do is give up.
If you do this then the horse has won and knows exactly what to do next time.
The most effective method to use when the horse is on the run is to keep him on the Move, not allowing him to run to a safe distance then put his head down to eat grass.
If the horse stops to approach you or turns to face you, then take up a more relaxed position with your arms down and eyes soft.
Approach him slowly and quietly talking to him in a gentle manner.
If he decides to run away from you keep him moving, waving your arms or a stick around, until he turns to you or approaches you again.
The horse will eventually learn that it is easier to be caught than constantly chased around the field.
When you do catch the horse do not shout or pull on the lead rope, instead reward him with a stroke and tit bit so he learns that it is a far more pleasant experience to be caught.
Naughty horse
Reward good behaviour and the horse will soon learn.