The inventor of the World Wide Web has said governments and companies "must not shy away" from giving the public free access to sensitive information.
Sir Tim Berners-Lee, who launched the web on Christmas Day 1990, argued that open data was essential in " fighting poverty, accelerating industry and innovation, and reducing corruption".
It comes as the 58-year-old computer scientist is due to present a report which found that while more than half (55%) of 77 countries surveyed have open data policies in place, less than 10% of key government data is available and truly open for re-use.
Speaking ahead of an open government summit he will address in London today, Sir Tim said: "It is important that efforts to open up data and information are meaningful and lead to real change.
"Governments and companies must not shy away from publishing contentious datasets if they contain information that could be used to dramatically improve people's lives."
The new barometer which Sir Tim will present f ound that the UK was the worldwide open data leader, followed by the US, Sweden, New Zealand and Denmark and Norway, who tied for fifth place.
It claims that controversial data such as company and land registers is among the least likely to be released, possibly due to a reluctance to drop lucrative access charges or hide politically sensitive information, or both.
The open data movement argues that information should be freely available for people to use and publish, without controls such as copyrights or patents.
It holds that "a piece of data is open if anyone is free to use, reuse, and redistribute it - subject only, at most, to the requirement to attribute and/or share-alike."
Detractors say that it raises concerns about privacy and the use of taxpayer money in costly data c ollection, "cleaning", management and dissemination.