The UK Government cancelled a working group set up with Ecuador to find a way of resolving the future of Julian Assange, the WikiLeaks founder has claimed.
Foreign Secretary William Hague agreed to the group after meeting Ecuador's foreign minister Ricardo Patino last year to discuss Mr Assange, who has been living in refuge in Ecuador's embassy in London for the past two years.
On the eve of the second anniversary of Mr Assange's dramatic arrival at the embassy, he revealed that the working group was not meeting.
In a conference call from the embassy, the WikiLeaks publisher said a six-member team had been established during Mr Patino's visit to London with the intention of studying legal and diplomatic issues.
Mr Assange said that following the granting of asylum last year by Russia to US whistleblower Edward Snowden, the UK Government had "unilaterally" cancelled the working group.
Mr Assange has been granted political asylum by Ecuador as he fights to avoid extradition to Sweden, where he faces sex allegations by two women.
He fears that if he goes to Sweden he will be taken to the United States, where a long-running investigation is continuing into WikiLeaks and its involvement with former solder Chelsea Manning, who has been jailed for 35 years over the leaking of secret intelligence.
Jennifer Robinson, a legal adviser to WikiLeaks, said a fresh challenge will be made next week to the Swedish authorities after "new information" was received.
Mr Assange has offered to be interviewed by Swedish investigators inside the London embassy, but they have declined to travel to the UK to question him about the allegations.
Mr Robinson added that a letter from more than 30 free speech organisations will be sent to the US attorney general Eric Holder next week calling for him to "close down" the investigation into WikiLeaks.
Mr Assange said Mr Holder should drop the four-year long investigation or resign, accusing the official of using "weasel words" when asked about the case.
Asked how he was coping with living inside the embassy, housed in a small building close to Harrods in Knightsbridge, Mr Assange said other people were in far more difficult positions, including Chelsea Manning.
He also criticised the Metropolitan Police for "gathering intelligence" from people who visit him inside the embassy.
The police operation, which involves a 24-hour guard outside the building, has cost several million pounds.
Mr Assange claimed police were "aggressively demanding" addresses and identity details from people who visit him, which he said caused difficulties for him in his ongoing work for WikiLeaks.
He said he had been watching World Cup games - supporting Ecuador - but said the reception wasn't good.
"Perhaps that makes it difficult for the bugs to travel through the walls as well."
Michael Ratner, Mr Assange's US legal representative, said the investigation in the US had not "lessened" since it was launched four years ago.
He said he believed the WikiLeaks founder would face similar treatment to Chelsea Manning if he was extradited to the US, including solitary confinement, being held in underground cells and a lengthy prison sentence.
He added that Mr Assange was in "limbo", effectively in custody for almost four years after he spent some time under house arrest before seeking refuge in the Ecuadorian embassy.
WikiLeaks spokesman Kristinn Hrafnsson said "painstaking" efforts had been made to reverse a banking blockade, which had hit donations to the whistleblowing organisation.
"I hope we can announce an important new milestone in that battle," he said, adding that secret documents were also due to be released by WikiLeaks "in the field of international negotiations".
A vigil will be held by Mr Assange's supporters outside the embassy tomorrow to mark the second anniversary.
A Foreign Office spokesman said: "We have neither cancelled nor suspended our working group with the Ecuadorian authorities, but remain as committed as ever to reaching a diplomatic solution to this situation.
"As ever, we look to Ecuador to help bring Mr Assange's difficult, and costly, residence to an end."