In the summer of 2004. Marthin De Beer was riding high as the head of Cisco Systems’ enterprise telephony business. The group, founded in the late 1990s, had enjoyed explosive growth under the South African’s leadership. By mid-2004, it was bringing in $500m in sales each year. It would soon become the world’s biggest provider of internal telephone networks to business.

For all its success, Mr De Beer’s group was something of an anomaly inside Cisco. The company, which makes most of its money from sales of internet switches and routers, had typically relied on acquisitions and partnerships to enter new markets. Enterprise telephony was the first business Cisco had ever started from scratch.