IBM has hit out at its arch rival Microsoft, alleging that it is "milking customers" with its software designed for mobile internet use.
It claims that some add-ons to Microsoft products lock customers into using only software designed by Bill Gates's company.
The move comes as US judge Thomas Penfield Jackson is due to give his verdict on whether Microsoft should be broken up to prevent it stifling competition.
IBM's argument centres on WAP, the established industry standard for downloading internet data on to mobile phones. Analysts predict that mobile phone companies and operators are just six months away from making internet- compatible phones widely available.
In an interview with the Independent on Sunday, Dr Mark Bregman, general manager of Pervasive Computing, the IBM division which is leading its development of mobile internet computing, said: "We want to have one set of open standards. Our view is that this will benefit the market and allow it to develop rapidly.
"But Microsoft extends them [the open standards]. Once you go so far with Microsoft, you can't go back. Microsoft traps customers and milks them for what they are worth."
IBM has taken a whiter-than-white approach to mobile internet standards by claiming that all its mobile internet products will work on any WAP device. Another IBM insider attacked Microsoft's mobile internet browser, claiming that, while on a general level it was WAP-compliant, "it supports other services which extends the way it operates making it proprietary".
The WAP standard was established when industry heavyweights, including Nokia, IBM and Ericsson, formed the WAP Forum, based in the US.
A board member of the Forum, who asked not to be named, said: "Microsoft came around very late to the idea of WAP. For many years Microsoft said that WAP was irrelevant.
"But in the middle of last year it approached the Forum and said that it needed a seat on the board.
"The board rejected Microsoft, but it was allowed to join as a Forum member."
Microsoft last week denied that it was flouting open standards for mobile internet use. Dilip Mistry, marketing manager for wireless and mobiles, said: "There is a lot of confusion over open standards. WAP is an industry standard. But it has some limits to it, so we do need to bolt things on to it."
But he said that Microsoft first gets approval from two industry bodies before issuing new "bolt-ons" and he denied that these would only run on Microsoft software - including its browser.
A telecoms analyst, who asked not to be named, said: "Open standards are a bit of a minefield. Microsoft's products technically conform to the standards, but they do have extra features which are non- standard. Microsoft does have a reputation for being proprietary."
Microsoft's reputation was hit when it was accused by the US Department of Justice and 19 states, of exerting monopoly power to crush internet browser company Netscape.
Whatever the outcome of the investigation, the development of software for mobile internet use will be key to its future strategy.
It has formed alliances with France Telecom, One2One and Orange, and has just completed mobile data accessing trials with Cellnet.
Meanwhile, IBM last week announced alliances with Motorola, Bank of Scotland, Spanish bank Bankinter and Cellnet to develop mobile internet access. IBM is also planning to introduce "bluetooth" chips in all its personal computers at the end of April.
This will invisibly link the PC with other devices by radio waves. For example, a person with a WAP-enabled mobile phone will be able to access files on the PC without a physical link.