Thousands of deaf and disabled people across the UK have told the BBC of the devastating impact the pandemic has had on their lives.
Most said their disability had worsened and more than 2,400 said routine, often vital, medical appointments had been cancelled.
More than 3,300 people took part in the research carried out by the BBC.
Disability charity Scope said the findings confirmed that disabled people's needs "had been forgotten".
The findings paint, for the first time, a comprehensive picture of a hidden fallout of Covid-19.
Nearly 100 more disabled people also contacted the BBC wanting to share their stories. Many of them had experienced huge physical and mental decline since March 2020.
2,604 said mental health had got worse
2,427disability had deteriorated
683had seen all of their appointments cancelled/unable to attend
241had not left house at all
There were young people with autism who had attempted suicide because they could no longer cope with drastic changes, others were isolated and alone, their support networks gone or hours of care cut.
Access to healthcare was a huge issue - one woman was told not to go to hospital if she contracted Covid as this might put her more at risk.
A family told how care had been almost stopped for their disabled daughter, while her father, who had had Covid, was offered a range of treatments.
Fourteen-year-old Josselin has a rare genetic condition, which means she has hearing loss, a vision impairment, can't walk or talk and is fed through a tube.
Her family, who live in Wiltshire, have a vital network of services they rely on to keep her well - physiotherapy, speech and language therapy, occupational therapy, respite care. All of that stopped in March 2020.
"Josselin really struggled. She just shutdown," says her mother Karen Tilley. "I never thought [she] would suffer from depression like that.
"After about a month she started pulling her hair out and picking at her skin, she had cuts all over her arms."
'Lack of support'
Josselin was prescribed anti-depressants and anti-psychotic medication. She was also given prescription drugs like diazepam to cope with the pain she was having in her hips and her spine because of a lack of physiotherapy.
"Suddenly she was put on all these new medications. There was just no support for us at all - it was horrendous."
She's not ever going to walk and talk so they just don't bother with her
At the beginning of this year, Josselin's dad Lee, 43, caught Covid-19. He spent five weeks on a ventilator in intensive care.
Lee is back home making small and slow steps to, the family hope, a full recovery. But the difference between the support he is offered and the treatment his daughter receives is stark.
His calendar is full of medical appointments. He has an occupational therapist, a physiotherapist, and he has been sent equipment to help him regain his mobility.
But for Josselin, her cochlear implant, which needs retuning every few months, has not been checked for nearly two years. Her last eye test was over the phone, she's not had any face-to-face physiotherapy since March 2020, and her walking frame no longer fits.
"It feels like it's because she's disabled so it's not worth bothering with," says Karen. "She's not ever going to walk and talk so they just don't bother with her."
All the people we have spent time with over the past few months have shared their own, heart-breaking stories. Considering everything they have had thrown at them this past year, they have managed to get through it the best they can, almost entirely on their own.
But what really hit me is that none of them kept a "who had it worse during Covid" scorecard.
Yes, they all pretty much described themselves in one way or another as "the forgotten ones", but they were all incredibly measured and understanding of the fact that the pandemic has touched us all in very different ways, disabled or not.
Freelance journalist Raya Al Jadir, 43, uses a ventilator. She was told by her specialist doctors that if she caught Covid-19, she should not go to hospital because the level of care she would need could not be guaranteed.
If I did end up in hospital and I was really sick - who was going to fight for me?
She was also warned that it was unlikely that she would be considered for life support.
"It made me feel alone and isolated. If I did end up in hospital and I was really sick - who was going to fight for me?"
Raya was one of the hundreds of disabled people who told the BBC that they would avoid going to hospital during the pandemic.
From March 2020 to May 2021, Raya did not leave her house for fear of catching Covid.
Shielding may have officially ended but there are still many disabled people living an isolated existence. Nearly 2,000 told the BBC that they had left their house on only a few occasions since the start of the pandemic, with almost 250 saying they had not ventured outside since March 2020.
At the end of May, Raya finally left her London flat.
"Breathing the air, seeing the clouds made me feel part of the world again.
"As a disabled person, I feel like the weakest link in society. And now, because of Covid-19, no-one knows what to do with the weakest link.
"I don't think my life will ever return to what it was before March 2020."
'Never happen again'
One of the biggest disability charities in the UK, Scope, has said the BBC's findings "confirm the government's failure to provide support for disabled people throughout the pandemic."
"Millions spent months shielding, having to battle for basic support like healthcare, supermarket deliveries, financial support and social care," said James Taylor, executive director at disability equality charity Scope. "Horrifying reports of DNRs [do-not-resuscitate orders] being placed on people without their consent left many fearing they'd not get treatment if they caught the virus.
The government "must take bold action now to put disabled people at the heart of the recovery, and end the growing inequality".
The Department of Health and Social Care said it recognised the pandemic has been "incredibly difficult" for disabled people.
"Among other support, we have invested £2.4m to help charities offer vital projects to improve disabled people's physical and mental wellbeing.
"The government has provided a range of help for disabled people throughout this period and through our forthcoming National Disability Strategy we are going to go even further in addressing issues that disabled people say affect them the most."
Information and support: If you or someone you know needs support for issues about emotional distress, these organisations may be able to help.