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.