Whitehall departments could share details of your financial history, education and property wealth with each other without your consent, under plans being mooted by Government.
Departments could freely share people's private information, including driving licences, energy consumption and criminal records under controversial proposals to link thousands of public sector databases.
The proposals were revealed by the Telegraph this week, which said they appear in a "discussion document" worked up by the Cabinet Office Data Sharing Policy Team back in April.
The Government hopes that sharing such data, backed by new laws, would lead to benefits such as cutting fraud, monitoring economic growth and recording population shifts better, as well as identifying troubled families.
The papers allegedly say ministers are sensitive to potential public concern over the move, and fear the project could fail if the proposals led to arguments with privacy campaigners.
The plans will be included in a whitepaper to be released in the autumn, and if passed would change the way personal data is governed.
The Data Protection Act means data cannot be shared outside of one government department without police intervention, but
Whitehall would like to be able to improve policy making by, for instance, linking people's energy usage to information about their properties.
However, the plans also allow for personal data, not anonymised, to be shared in order to help groups such as the elderly. They come after a study in January found people trust central government bodies the most with their data.
A Cabinet Office spokesperson said: "Before a decision can be taken on whether to introduce draft legislation, it is important that a wide range of views, from within and outside government, are understood.
"The Cabinet Office is leading an open policy-making process, working in partnership with civil society and privacy organisations to develop policy proposals for areas where we believe data sharing, as one possible option, could significantly improve the way we currently work. This process is ongoing and we cannot pre-empt the solutions that it may produce."