Linux continues to prove its worth as a serious contender to Microsoft's Windows operating system (OS), according to research by analyst firm Context.

More than 500 VARs across Europe, including 85 from the UK, took part in Context's Linux survey in August. The results were published last week.

They showed that 30 per cent of VARs questioned are actively selling Linux-based computers. A total of 57 per cent said they planned to increase Linux sales.

The findings back last week's Vanson Bourne survey of 200 IT managers across the UK, which found two in five had switched from Windows to Linux.

Jeremy Davies, senior partner at Context, said: "If I was Microsoft I would be worried about Linux.

"There is a clear picture that emerges of Linux as a parallel market to Windows, governed by its own clear dynamics and structure, but dwarfed by the promotional activity and marketing spend associated with Windows.

"Cost is where Linux scores a major point, and the fact that it has an incredible support network, unlike proprietary software, makes it attractive to businesses.

"We were surprised at the number of resellers actively selling Linux. It seems the flow of the Linux business is happening without most of those outside the Linux world being aware of it."

Peter Dawes, sales director of Linux services and consultancy firm LinuxIT, agreed with Context's view.

"We have seen [Linux] sales move considerably from early adopters into mainstream computing over the past year, especially on the server side where we have seen huge growth," he said.

"Linux network infrastructure solutions are also popular in niche and vertical markets.

"On the server side Microsoft has every right to be worried. We are at the most challenging point for Linux, because Microsoft is taking it more seriously and the battle lines have been drawn."