While it is easy to blame bosses when things go wrong with a company, we must remember that rogue employees can also wreak havoc (Insecure bosses can pull organisations down, by Mr Simon Owen Khoo; June 23).

There are numerous reports of fraud committed by employees, and employees who embarrass their companies.

These incidents can be relatively minor, like inflating claims or passing off personal expenses as company expenses.

Some employees play pranks that end up being posted on the Internet, blackening the employer's reputation.

Other employees, in an effort to please their bosses, may bend or break the rules, or take outsized and unauthorised risks.

Much harm is also done when an employee leaves a company and sets up a rival firm using stolen technology and client lists.

Such former employees may build a "backdoor" into the company's IT system and do damage by deleting files, making private e-mails public or distributing damaging pictures.

It is getting harder to control information.

A single USB stick can contain more company data than many typewritten pages, and a mobile phone can be turned into a listening device or a tool for hacking.

Firms need to focus on the people who have the greatest capacity to do harm, especially those who control money and information.

Employees are said to be a company's biggest resource, but they can also be its biggest liability.

Francis Cheng