The inventor of the World Wide Web says governments and companies "must not shy away" from giving the public free access to sensitive information.

Sir Tim Berners-Lee, who launched the web in 1990, says open data is 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 in London today which states 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.

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 lives."

The new barometer which Sir Tim will present found the UK was the worldwide open data leader, followed by America, Sweden and New Zealand. Denmark and Norway tied for fifth place.

It claims 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.

Detractors say it raises concerns about privacy and the use of taxpayer money in costly data collection, "cleaning", management and dissemination.