Julian Assange speaking from the balcony of the Ecuadorian embassy in London

A United Nations human rights expert is calling on the UK and Swedish governments to accept the findings of a UN group over WikiLeaks founder Julian Assange.

Alfred de Zayas said the two countries should set a "good example" and follow the decision earlier this month by the UN Working Group on Arbitrary Detention that Mr Assange should be free to leave the Ecuadorian embassy in London.

Authorities in Britain and Sweden have rejected the finding, saying Mr Assange has detained himself by seeking refuge in the embassy after facing allegations of sexual misconduct in Sweden.

Mr de Zayas said in a statement that the non-binding international order requires a "consistent and uniform" application of international law.

He said: "The findings of the Working Group on Arbitrary Detention should be accepted and their recommendations implemented in good faith. Especially those states who claim to be at the vanguard of human rights should give a good example, even if they do not agree with the conclusions of UN experts.

"The international order depends on the consistent and uniform application of international law, and is undermined when states pick and choose. The concept of human dignity is holistic. An a la carte approach to human rights erodes the credibility of the entire system.

"It is important that countries that regularly engage in naming and shaming of other countries accept United Nations rulings when they themselves are implicated. It is a matter of intellectual honesty. Prompt implementation of the Working Group's opinion would set an example for the rest of the world."

Mr Assange has been living in the embassy in central London for over three years after being granted political asylum by the Ecuador government.

He believes that if he is extradited to Sweden he will be transported to the United States for questioning over the activities of WikiLeaks.