LONDON — Julian Assange, founder of Wikileaks, the whistle-blowing website, lost his appeal Wednesday in the highest British Court against extradition to Sweden on rape and sexual molestation charges.

Assange did not attend the 10-minute judgment passed down by British Supreme Court, where dozens of supporters waving placards in support for his cause stood outside the entrance.

Judge Nicholas Phillips, presiding over the seven-member panel, told the court the judgment “was not an easy decision to make.”

Assange’s defense argument was that the Swedish prosecutor who issued the European Arrest Warrant demanding his extradition was not a valid judicial authority.

Phillips told the court that the panel eventually gave a majority vote of five to two, ruling that “the Swedish public prosecutor was a judicial authority and the request for Mr. Assange’s extradition has been lawfully made and his appeal against extradition is accordingly dismissed.”

Dinah Rose, Assange’s defense attorney, was given two weeks to consider the judgment and confer with her client and make a further application and possibly reopen the case on a legal point.

The 40-year-old Australian-born Assange is under house arrest in eastern England in the mansion of a supporter. He denies the charges and his fight against extradition is based on the grounds that once in Sweden he could be extradited to the United States to face charges for leaking State Department documents on the Internet.

The crowd of supporters gathered outside the court with placards and banners saying “Free Assange” and “Free Bradley Manning,” referring to the U.S. Army analyst suspected of releasing secret diplomatic documents to Assange for his website. Manning is presently in custody in the U.S. awaiting trial.