By Mark Easton
Home editor, BBC News
A giant database of people's personal details could be created at Whitehall under government plans which ministers say will help improve public services.
Critics say there is a drift towards "Big Brother"
Tony Blair is expected to unveil the proposal in Downing Street on Monday.
Strict regulations currently prevent one part of government sharing personal information it holds with another.
Ministers argue the data-sharing rules are "overzealous" but the Conservatives say relaxing them would be "an excuse for bureaucrats to snoop".
So-called citizens' panels will gauge public reaction to relaxing privacy procedures so people do not have to repeat personal information to different public bodies - particularly at times of stress such as a family death.
Officials think current rules are an obstacle to improving public services.
But such data-sharing is controversial. As well as criticism from the Conservatives, the information commissioner - the data watchdog - has warned Britain may be "sleepwalking into a surveillance society".
The idea of allowing different Whitehall departments to access centrally-held data emerged during the government's policy review of public services.
The review team, headed by Work and Pensions Secretary John Hutton, has concluded that it is difficult for services to be as flexible and light-footed as people want because of rules on data.
The department cites an example of a family who had a total of 44 contacts with government over 180 days trying to make the necessary arrangements after a family member died in a road accident.
Too often, says the review team, it may be legally forbidden to use information other than for a single purpose.
At other times services may assume there is a legal barrier when there is none.
And sometimes, the review found, the traditional culture of separate government departments contributes to delays and barriers.
However, the government wants to involve the public in deciding how to balance individual privacy against possible improvements in customer care in the public sector.
Five citizens' panels of 100 people are being recruited by the polling organisation Ipsos Mori.
In a process known as "deliberative democracy", the panels will be briefed on the pros and cons of different approaches to public services and then invited to make their decision.
Their views, say ministers, will then feed into government policy.
Among the issues the panels will consider are: the role of the citizen and state; rights and responsibilities; and customer care within public services including the idea of data-sharing.
This is not the first time the government has proposed sharing sensitive personal information between Whitehall departments.
Last year the Department of Constitutional Affairs (DCA) claimed relaxing rules on data-sharing would help tackle ID fraud and would also identify those "in need".
But Shadow Constitutional Affairs Secretary Oliver Heald said: "Step by step, the government is logging details of every man, woman and child in 'Big Brother' computers."
Shadow Home Secretary David Davis said: "The chances of it actually solving crimes is pretty small.
"The chances of it costing over £20bn is very high. It will be a white elephant."
Information Commissioner Richard Thomas, who is charged with ensuring the state does not collect too much information about citizens, has also been critical of data-sharing and already expressed concern at the Citizens' Information Project.
That is a plan by the Office for National Statistics to create a population database for use by public services.
"There are reasons why we need to promote better information," Mr Thomas said, "but whether the right answer is to create a database should be questioned."