James Horwill: At centre of controversy over alleged stamping

Horwill was cited after the Wallabies lost the opening Test against the British and Irish Lions in Brisbane 23-21 but was cleared by judicial officer Nigel Hampton QC following a four-hour hearing.

The IRB have asked for the incident to be looked at again though, leading to a swift response from the ARU.

"The International Rugby Board has confirmed to the Australian Rugby Union that it will appeal the James Horwill disciplinary decision following an extensive review of the case," read a statement on the IRB's official website.

"As the 2013 British and Irish Lions Tour falls within the scope of the IRB merit-based appointment scheme approved by the IRB Council, the right to appeal any decision arising from matches under the scheme.

"Furthermore, given its duty to preserve player welfare at all levels of the Game, the IRB is compelled to further examine potential acts of foul play which either potentially or in reality impact on the preservation of player welfare.

"The appeal will be heard by Graeme Mew (Canada) following the second Test between Australia and the British & Irish Lions. Horwill is free to play pending the outcome of the appeal."

Any appeal will not be heard until after Saturday's second Test, leaving the lock free to play in Melbourne.

But the ARU were clearly unhappy with the IRB's decision to become involved in the matter and have accused them of disrupting the "positive atmosphere surrounding the tour".

"This is an unprecedented step taken by the IRB in what is the most important rugby event staged in Australia since the 2003 Rugby World Cup," said ARU chief executive Bill Pulver in an official statement.

"While we respect the right of the IRB to intervene, we also respect the knowledge and experience of appointed - and independent - judicial officers, and their expertise to consider evidence and reach sound findings," he said.

"James Horwill was cleared of the stamping charge as per the IRB's established judicial process.

"We are surprised and disappointed that the finding of Mr Hampton is now not only under question but deemed to be 'erroneous'.

"In the midst of an extraordinarily successful series that has been 12 years in the making, the re-hearing process has the potential to cause serious disruption to the Wallabies and the positive atmosphere surrounding the tour.

"The ARU in no way condones foul play. However, the process was followed according to IRB regulations and the decision of an independent judicial officer handed down. What has occurred subsequently is without precedent."

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