Cuts to social services have "totally neglected" the needs of disabled people and created a "human catastrophe", the chairwoman of a UN human rights committee has said.
Theresia Degener, who leads the UN's Committee on the Rights of Persons with Disabilities (CRPD), accused British politicians of failing vulnerable members of society.
UK officials have also faced allegations of misrepresenting the impact of policies through unanswered questions, misused statistics and statements on policies and legislation.
Ms Degener said evidence seen by the committee and a review it carried out last year made clear the impact of austerity policies in the disabled.
She said the controversial "fit to work" tests were based on a correct assumption that disabled people could find employment.
"However, evidence before us now and in our inquiry procedure as published in our 2016 report reveals that social cut policies have led to a human catastrophe in your country, totally neglecting the vulnerable situation people with disabilities find themselves in."
The CRPD previously said welfare reforms have led to "grave and systematic violations" of disabled people's rights, findings the Government said it strongly disagreed with.
The committee is now conducting a much wider investigation to assess the UK's progress in implementing the UN Convention on the Rights of Disabled People, as part of a periodic review all nations signed up to the convention must go through.
Officials have faced two days of grilling from the UN panel in Geneva, which has criticised the UK's approach.
Major groups including Disability Rights UK and the Equality and Human Rights Commission also warned that disabled people's rights under the convention are at risk of being breached.
Stig Langvad, the committee rapporteur for the UK, said he was "deeply concerned" about the Government's failure to act on CRPD's previous report.
He added: "I could provide a long list of examples where the state party does not live up to the convention."
Concerns were also raised about a disconnect between the Government's answers and evidence, compared with the actual experiences of disabled people.
Karen Jochelson, head of the office for disability issues at the Department for Work and Pensions, led the British delegation.
She said in her closing remarks that it was right the UK was scrutinised carefully and it was determined to remain a global leader in disability issues.
The Government says, as a share of GDP, the UK's public spending on disability and in capacity is higher than all other G7 countries other than Germany, while its focus has been on helping disabled people achieve their potential in the job market and wider society.