CRIMINALS on tough policeman Mir Zhang's new beat had better head for the hills - as he puts on a display of his hard-headed approach to law and order. The 48-year-old bobby on the beat in Hei Longjiang province, China, has studied deadly kung fu techniques for more than 20 years which has left him apparently invulnerable to pain and injury. In a display for colleagues he shrugged off bricks smashed on his skull with a sledgehammer, forced a steel spear into his throat and headbutted heavy stoneware pots to pieces as they flew the air. Mr Zang said: 'Anyone can do what I do as long as they find a good master and study hard. 'I'm not a cruel man but I don't like criminals and I won't hesitate to use what skills I have on them if I have to.' Metro