The United Nations has insisted a controversial visit by an inspector who slated the so-called bedroom tax was arranged "in full co-operation" with the UK government.
A UN spokeswoman told HuffPost UK that Raquel Rolnik "undertook an official visit to the United Kingdom at the invitation of the Government".
It confirmed it had received a furious letter from Tory chief Grant Shapps, who it referred to as 'Chairman Shapps', but it has not yet decided whether to reply.
After Rolnik posed with anti bedroom tax campaigners and gave an interview to The Guardian branding the policy "shocking", she was branded a "Brazil nut" in some newspapers and Shapps rushed off an angry letter to UN Secretary General Ban Ki-Moon, demanding answers and accusing her of political bias.
The secretary general's office told HuffPost UK a letter had been received from "Chairman Shapps".
But a spokeswoman said: "I don't have any reply letter to share."
Asked again whether a response would be sent, she said she believed a reply was "being considered", but had no further information.
The Conservative Party confirmed nothing had been received to date.
The UN told HuffPost UK: "Ms Rolnik undertook an official visit to the United Kingdom at the invitation of the Government.
"Her visit was organized in full cooperation with the Government and she met with all relevant Government departments at the highest level possible in England, Scotland and Northern Ireland."
It said Rolnik had been "independent and unpaid" and serving in her personal capacity.
This would allow her to report back to the UN Human Rights Council "in all impartiality", she said.
The UN spokeswoman went on: "The preliminary views and recommendations expressed by the Special Rapporteur are her own, based on information and testimonies received from numerous groups and individuals during and prior to the visit, and on constructive discussions with senior government officials.
"She will continue to engage with all stakeholders as she develops her final report and recommendations, to be submitted to the Human Rights Council in March 2014."