The letter followed an earlier warning from Sir Liam that millions of Britons could fall victim to swine flu in the coming months. Government officials admitted last night that illness rates from the virus could reach 50 per cent.

Primary care trusts are now being briefed to expect that the pandemic could affect as much as 40 per cent of the workforce before the end of the year, with many worried that there could be a surge of cases in the autumn, according to health industry sources.

The Department of Health sought to reassure the public last night. A spokesman said: "Previous pandemics have seen total illness levels of 25-35 per cent. So our plans are as robust as possible, we have based them on illness rates of 50 per cent, though we do not anticipate it being this high in the current pandemic. Based on this figure, the workforce could be reduced by 15-20 per cent at the pandemic's peak. In the unlikely event that every school closed, this could rise to 35 per cent." He said it was impossible to predict when the pandemic would peak, but added: "As part of ongoing planning, the NHS is being asked to ensure that antiviral collection points could, if needed, be put into action in a week."

Keen to avoid panic, the Government is careful to present official statistics showing "laboratory-confirmed" cases, which currently stand at 2,244. Yet the true scale of infections is far higher than headline figures suggest. The total number of cases either confirmed by laboratory tests or "clinically presumed" currently stands at 3,725.

Working with doctoral students Paul Harvey and Jason Stoner, Hochwarter surveyed more than 700 people who work in a variety of jobs about their opinions of supervisor treatment on the job. The survey generated the following results:

Thirty-one percent of respondents reported that their supervisor gave them the "silent treatment" in the past year.

Thirty-seven percent reported that their supervisor failed to give credit when due.

Thirty-nine percent noted that their supervisor failed to keep promises.

Twenty-seven percent noted that their supervisor made negative comments about them to other employees or managers.

Twenty-four percent reported that their supervisor invaded their privacy.

Twenty-three percent indicated that their supervisor blames others to cover up mistakes or to minimize embarrassment.

According to the researchers, "Employees stuck in an abusive relationship experienced more exhaustion, job tension, nervousness, depressed mood and mistrust. They also were less likely to take on additional tasks, such as working longer or on weekends, and were generally less satisfied with their job. Also, employees were more likely to leave if involved in an abusive relationship than if dissatisfied with pay."

An Ohio company has embedded silicon chips in two of its employees - the first known case in which US workers have been "tagged" electronically as a way of identifying them.

CityWatcher.com, a private video surveillance company, said it was testing the technology as a way of controlling access to a room where it holds security video footage for government agencies and the police.

Embedding slivers of silicon in workers is likely to add to the controversy over RFID technology, widely seen as one of the next big growth industries.

"There are very serious privacy and civil liberty issues of having people permanently numbered," said Liz McIntyre, who campaigns against the use of identification technology.

But Sean Darks, chief executive of CityWatcher, said the glass-encased chips were like identity cards. They are planted in the upper right arm of the recipient, and "read" by a device similar to a cardreader.

"There's nothing pulsing or sending out a signal," said Mr Darks, who has had a chip in his own arm. "It's not a GPS chip. My wife can’t tell where I am."

Three-fourths of the companies monitored employees' Web site visits. Almost two-thirds said that monitoring was "ongoing" or "routine."

Just over half said they monitored phone calls. About one in five said they taped calls.

More than half reported using video monitors.

The majority of the technology adopted by businesses in the future will have its roots in the consumer market, said analyst Gartner which also believes that companies will soon start encouraging employees to purchase their own PCs.

In a research note released last week, Businesses Need to Explore Consumer Technology Before the Next Internet Revolution Leaves Them Behind, the analyst group claims that while traditional enterprise software remains critical, many functions can be accomplished through technologies designed for consumers.

Applications that are making inroads into enterprises include the Google Desktop, AOL IM, and Skype's voice-over-IP software, Gartner said.