Image caption The Wikipedia entry for George W Bush was regularly subject to malicious editing

The online encyclopaedia Wikipedia says it has taken an "important step" towards making it easier to edit some of its most controversial articles.

Up to 2,000 articles, including a page about former US President George W Bush, will have their strict editing restrictions relaxed.

Users will now be able to submit changes to the selected pages for review by senior editors.

It is part of Wikipedia's ongoing efforts to curb vandalism of the site.

Wikipedia's founder Jimmy Wales told BBC News that the new system, called "pending changes" will allow the site "to open up articles for general editing that have been protected or semi-protected for years.

"That's what is exciting about this," he said.

False reports

Wikipedia encourages editorial changes from everybody who comes to the site.

However, it has been plagued by persistent problems such as the malicious editing of entries, and repeated editing of controversial topics.

These have had to be semi-protected for years just because they are too tempting for naughty people to try something funny Jimmy Wales, Wikipedia founder

As a result, the site has introduced a number of levels of protection that can be applied to articles.

For example, new or anonymous users could previously be prevented from editing "semi-protected" articles, and were forced to suggest changes on a discussion board attached to each article before they could be incorporated.

Semi-protected articles cover a wide range of subjects including Iceland, David Cameron, George W Bush and even homework.

The new changes should make it easier for users to contribute to these pages, the site says.

Mr Wales said that he was pleased to see the pages opening up again.

"These have had to be semi-protected for years just because they are too tempting for naughty people to try something funny," he said.

"But semi-protection has prevented thoughtful and sincere newcomers from making good changes."

Pending Changes will be introduced at 11pm GMT on 15 June.

Editing review

Any edits to articles in this category are subject to review from an established Wikipedia editor before publication, although anyone can still view changes that have been proposed.

For the duration of the two month trial, Wikipedia users will notice a small magnifying glass, in place of a padlock, on included articles.

Image caption A new tab has been introduced to reflect articles that have changes pending

In a blog post, Wikipedia said: "The icon, on the upper right corner of the article, represents an important step that Wikipedia volunteers have taken to open up articles that were previously protected from editing.

"At present, only about 0.1% of the 3.3 million articles on the English Wikipedia are under edit protection.

"This tool should help reduce disruptive edits or errors to these pages while maintaining open, collaborative editing from anyone who wants to contribute."

Anyone can view proposed edits by clicking on the "pending changes" tab, alongside the "edit" and "history" tabs on a Wikipedia entry.

The software that enables the new feature was originally developed for the German version of Wikipedia, where it is called "flagged revisions".

In Germany, edits on all articles are subject to review, and it is likely that some observers will see this pilot as the first step towards such a system in English.

Mr Wales said that was "extremely unlikely" and "neither necessary nor desirable".

"The Germans seem happy with it, but they are also going to be closely watching the English system, and I'm sure they'll at least consider switching if the results are good," he said.

Michael Peel, secretary of the independent non-profit organisation Wikimedia UK, told BBC News that it had taken "a long time to find consensus" on how best to run the trial.

Mr Wales called for a similar change in 2009, after Wikipedia articles wrongly suggested for a short time that two US senators had died.

In a blog entry, Mr Wales said the "nonsense" of the false reports would have been "100% prevented" by a system that involved editors and said he wanted the changes to be implemented as soon as possible.

The suggestion provoked a storm of comments on his site, with many encyclopaedia editors saying the proposal was unworkable.

Wikipedia said the decision about which articles to include in the new trial, up to an initial limit of 2,000, will be taken by the Wikipedia community.