Some 48pc of companies have stopped workers from �tweeting� and posting updates while at work over the past year, with 45pc fearing business reputation was at stake, the survey by Lewis Communications and HCL Technologies found.

Vineet Nayar, HCL Technologies� chief executive, said: �It is quite remarkable that in this day and age, many employers are still putting their employees� interests as a low priority by not allowing them to use sites like Facebook.

�Banning them outright will impact employees� approach to work in a negative way, having a detrimental effect on the business as a whole.�