David has decided to incorporate his Mexican Restaurant business which he has run previously as sole trader. After careful consideration with you, he has set up a limited liability company called Mexican Cantina Ltd in which he is the sole shareholder with 10,000 fully paid-up shares at $1 per share. He is also joint director of Mexican Cantina Ltd with his wife Claire. Explain the legal principle which limits the personal liability of Julian as a shareholder of Mexican Cantina Ltd. Which legal case established this legal principle? (5 marks)