Downing Street says it is obliged by law to extradite Assange to Sweden and 'it is our intention to carry out that obligation'

Downing Street has said Britain is still committed to seeking a diplomatic solution with Ecuador in the standoff over the proposed extradition to Sweden of Julian Assange.

But British diplomats in the Ecuadorean capital, Quito, and in other regional capitals have communicated the message that David Cameron is adamant Assange will not be granted safe passage. They say Britain is under a legal obligation to extradite Assange to Sweden to face allegations of sexual misconduct.

The government's thinking was outlined by the prime minister's spokesman at the weekly Downing Street lobby briefing. The spokesman said: "Our hope is that we can reach a diplomatic solution and we are doing what we can to achieve that.

"We will not grant safe passage for Mr Assange. Under our law, having exhausted all the options of appeal, we are obliged to extradite him to Sweden. It is our intention to carry out that obligation. We will continue talking to the Ecuadorean government and others to try and find a diplomatic solution here."

On Sunday, Assange appeared on the first-floor balcony of the Ecuadorean embassy in Knightsbridge to declare he was facing a "witch-hunt" led by the US. Assange was granted political asylum last week by Rafael Correa, Ecuador's president, two months after the WikiLeaks founder sought refuge in the embassy.

Ecuador tried to maintain diplomatic pressure on Britain, which warned last week it could revoke the diplomatic status of its embassy, by convening a meeting of foreign ministers from the 12-strong Unasur South American union in Guayaquil, Ecuador's largest city. The ministers condemned the British warning over the status of Ecuador's embassy but declined to endorse Correa's decision to grant asylum to Assange.

Downing Street said British diplomats had been explaining to members of Unasur why Britain was determined to extradite Assange. The prime minister's spokesman said: "We are obliged to extradite this man. He faces some very serious allegations in Sweden. The extradition case has been heard in our courts. We have been through the process. We now have to proceed with our obligation, which is to extradite him to Sweden.

"He [the prime minister] thinks we need to meet our obligations and that means extraditing him to Sweden. We will be making our position clear to the Ecuadorean government, to others in that region, to explain why this is the process and why we have to follow this process under the law."

The spokesman defended the Foreign Office's decision to write to Ecuadorean officials last week pointing out that Britain could, under the Diplomatic and Consular Premises Act 1987, revoke the diplomatic status of its embassy if it "ceases to use land for the purposes of its mission or exclusively for the purposes of a consular post". William Hague, the foreign secretary, denied Ecuadorean claims that this amounted to a threat to storm the embassy.

The prime minister's spokesman said: "All we were doing last week was setting out the position as it stands. We were simply clarifying the legal position, no more than that. We will continue to talk to the Ecuadoreans to try to find a way forward here."