Half of senior managers are unaware of their responsibilities to prevent staff accessing porn at work, according to a new research.

The survey found that 50% of managers had no idea of their "personal and civil liability for illegal and inappropriate images" in the workplace, and that two out of three companies have not kept their Computer Acceptable Usage Policy up to date.

Conducted by PixAlert and the Chartered Institute of Personnel and Development (CIPD) the poll also found that 70% of companies have had to discipline employees over viewing pornography at work, according to a survey published today.

While most companies have installed some degree of protection to prevent porn getting on to the network via email or the internet, nearly 70% have not installed technology capable of identifying "improper images" which can enter through desktop or laptop computers through memory sticks or other digital storage devices, including camera phones.

Imogen Haslam of the CIPD said that preventing porn from reaching the workplace was about more than just "sparing blushes," adding, "Employers need to have clear, consistent policies that leave no room for doubt in the minds of employees.

"A little tolerance could cause a lot of trouble later. They also need to keep up to date with the rapidly advancing array of technology that can make it easy for unwanted images to slip into the workplace unnoticed.

"This should not be left to the IT department alone. It's not computers that bring inappropriate or illegal images to work, it is people."