Two businessmen are set to become multi-millionaires when their company floats on the Stock Exchange.

Peter Lammer and Jan Hruska, who met when they were engineering research students at Oxford University in the 1970s, have built Sophos into a global business.

The firm, which makes anti-virus computer software, is planning to raise £100m to market a new product in the US, and is likely to be valued at up to £500m.