Digital minister Tom Watson used Twitter to announce his resignation on Friday, it has emerged.
Watson spent 18 months at the Cabinet Office and spoke often on IT-related issues.
Watson used a posting on the micro-blogging site to link to a letter written to Gordon Brown. He wrote, "I promised, Twitter friends, you'd get it first."
News of the Cabinet minister's resignation broke last week but was not confirmed until Friday, when Watson posted details on his blog.
Watson set up the Power of Information Task Force, which exists to advance the recommendations of the Power of Information Report, by Ed Mayo and Tom Steinberg, into the social and economic gains that could be achieved from better use of government data.
The Cabinet Office recently announced it is considering launching a website similar to the US's data.gov, which would make large data sets available to the public.
Watson said in his letter to Gordon Brown, "I would like to think that I have helped our government to think about information in new and better ways. I have tried to be a champion for the digital community, where lie some of our best and brightest talents and much of our nation's future success."
He attributed his resignation to the "painful" pressure that his high-profile job had placed on his young family.