The number of High Court defamation claims jumped 15% last year, marking the highest level for more than a decade, according to new research.

The claim is made by City law firm Reynolds Porter Chamberlain (RPC), citing analysis of recent official Judicial Statistics, which the firm says show that 298 High Court defamation writs were issued in London in 2009. The figure is up from 259 in 2008 and represents a near 50% increase over a three-year period.

The figure marks the highest level of High Court defamation claims since the 1999 Woolf reforms of civil procedure rules, which were designed to usher in faster dispute resolution and lead to more pre-court settlements.

RPC said that its analysis shows a rise in claims relating to allegations of involvement with extremist groups or terrorism and suggests that the general increase in claims could be attributed to the impact of the internet.

RPC media partner Jaron Lewis said: "This is the third year in a row where the number of claims has increased, firmly putting to bed the notion that libel law is not a serious challenge for the media."

Lewis added: "Despite efforts to reduce the likelihood of expensive defamation litigation, the number of claims has been creeping up consistently as claimants continue to rely on favourable laws to bring expensive and often unnecessary litigation through the courts."

RPC defamation specialist David Hooper told Legal Week: "The rise in celebrities bringing cases and the 'no win, no fee' culture has meant that there has been a significant increase in the number of defamation claims of late. There has also been a rise of people who have been falsely accused of terrorism bringing court action.

"This used to be an area that was largely represented by firms in the WC2 district of London, but the face of this is changing now."

The findings come as libel reform continues to rise up the political agenda, with the outgoing Labour administration unsuccessfully attempting to push through libel reform before this year's general election.

However, the incoming coalition Government in May promised to review libel law with a view to protecting free speech as part of a detailed policy agreement between the Conservative and Liberal Democrat coalition partners.

RPC's analysis is based on figures from chapter six of the Ministry of Justice's Judicial and Court Statistics 2009. Click here to see the original report.