Australia's skilled migration program has become a political football with all sides of politics trying to score points. Labor's calling for a crackdown on 457 visas, while One Nation's calling it a scam. But the boss of one of the country's most successful hi-tech companies is warning against an own goal. Atlassian's Mike Cannon-Brookes employs many skilled workers on 457 visas. He says the system is not being rorted and skilled workers are essential if Australia is to become the 'Innovation Nation'. Mike Cannon-Brookes sat down with Ticky.