WikiLeaks founder Julian Assange's battle to avoid extradition to the US will go to Britain's Supreme Court after he was granted the right to appeal a lower court ruling.

The High Court in London allowed Assange to appeal its decision that he could be sent to the US to stand trial on espionage charges. The decision is the latest step in Assange's long battle to avoid trial on a series of charges related to WikiLeaks' publication of classified documents more than a decade ago.