A decision to tighten regulations on disability payments "makes an absolute mockery" of the Government's commitment to deliver parity of esteem between mental and physical health, Labour has said.
Shadow work and pensions secretary Debbie Abrahams said the changes made to personal independence payments (PIP) would mean "restricted" access to support for people suffering psychological distress.
The Government moved to change PIP rules after it lost two rulings last year.
A tribunal said claimants with psychological problems who cannot travel without help must be treated like those who are blind, and those who need support to take medication should be assessed the same way as those managing therapies like dialysis at home.
Ms Abrahams was joined in condemning the Government's decision to tighten the regulations by Tory MP Heidi Allen who said the rulings had been made "for a reason".
Ms Abrahams secured an emergency Commons debate on the new PIP regulations.
Fellow Labour MP Helen Goodman (Bishop Auckland) intervened and said: "Do you agree with me that the Government seems to be in a place where the NHS is catching up with the need to treat mental health conditions properly but the other public services, whether that's DWP (Department for Work and Pensions) or the prison service, is simply stuck in the past and this must change?"
Ms Abrahams replied: "You are absolutely right. This makes an absolute mockery of the claim around parity of esteem."
Ms Abrahams said the tightening of the regulations was "nothing more than a shameful cut" as she linked the issue to Theresa May's words following the Westminster terror attack.
She said: "It's exactly a week since the horrendous attack in Westminster when four people including our colleague Pc Keith Palmer were murdered and 50 were injured.
"The following day the Prime Minister quite rightly said that she was, and I quote, 'Looking at what further support can be made available for victims in a wider sense because there would be people who were not physically injured in the attack but for whom there may be other scars, it's important to provide that support'.
"But the fact is with these new regulations, support for people suffering psychological distress is being restricted.
"Warm words need to be backed up with action."
Ms Allen, the MP for South Cambridgeshire, said later: "The courts have given us a loud and clear message today, mental health, you have got it wrong, and in this age where we are desperately trying to change society and its views on mental health and parity of esteem we have got to listen to the courts.
"They have given us a judgment for a reason."
Peers urged the Government to rethink its PIP plans on Monday by backing a Labour motion expressing regret at the changes and demanding a review of their impact on people with mental health conditions.
Implementing the tribunal rulings would cost the Government hundreds of millions of pounds and ministers have maintained that tightening the regulations is necessary to ensure PIP applies as originally intended.
Liberal Democrat former health minister Norman Lamb said the changes were "discrimination" towards people with mental health conditions and conflicted with efforts to offer equal treatment for mental and physical health.
Mr Lamb, intervening on SNP MP Corri Wilson (Ayr, Carrick and Cumnock), said: "Doesn't this run the risk of actually increasing stigma again of mental health, because it is saying to people very clearly that anxiety causing you to stay inside is not something that is really serious?
"And doesn't it completely conflict with the principle of equal treatment between mental health and physical health?"
His concerns were echoed by Labour's Stephen Timms (East Ham), a former minister, who said the move was "clearly a cut" to services.
Mr Timms told MPs: "Now the Secretary of State has said, 'Don't worry, people with cognitive impairments can still qualify for the highest rate of the mobility component', which may well be the case.
"But that is a different group of people. These changes explicitly carve out people whose mobility impairment arises from psychological distress."
Work and pensions minister Penny Mordaunt said mental health has "never been more prominent on any government's agenda before".
Ms Mordaunt, who refused to take interventions from opposition MPs as she replied to the debate, said: "I will not repeat the statistics about the numbers of people with a mental health condition receiving PIP more favourably than was on DLA."
She added: "Several members have concluded someone who is suffering from psychological stress that that would not count towards their scoring, and if they did suffer from psychological distress that they would be somehow excluded from scoring the maximum amount on the descriptors.
"That is not the case."
Ms Mordaunt said she would seek to place case studies in the House of Commons library supporting her argument due to a lack of time remaining in the debate.
She added: "If you're suffering from autism, or PTSD or depression or such conditions, you can score 12 points on that descriptor."
Copyright (c) Press Association Ltd. 2017, All Rights Reserved. Picture (c) Andrew Matthews / PA Wire.