Mr Miller leaves after 15 years as Mr Sugar's right-hand man. He has played an increasingly important role in liaising between the City and the troubled company, which has suffered from cut-throat price competition and is expected to report losses of about pounds 5m in full-year figures in October.
Mr Miller said Mr Sugar was 'the king of the consumer electronics industry', and leaving Amstrad would be a big wrench. But he decided to take the job because it was time to move on after 15 years at the company: 'And it was a fantastic offer - it's a great package, too good to turn down.'
He joins Sega on a three-year contract. He declined to disclose details of his salary, but he stressed he would not be paid compensation for leaving Amstrad, where he is on a shorter contract. He is thought to earn about pounds 130,000 a year.
'I've decided to leave and that's it. We are all very sensible here. We get paid for the job we do,' he said.
He remains at Amstrad until 22 September and will be replaced by Bordan Tkachuk, another Amstrad insider, who was director of the company's Australian subsidiary and responsible for its Far East sales operations.
He takes over at a difficult time for the company, and for the games industry. The Monopolies and Mergers Commission is investigating whether the industry has been guilty of unacceptable pricing policies, and is due to report in October.Reuse content