It was a cold day in February five years ago when a psychologist sent by the local authority issued a chilling warning to Sinead: Give up your rights to protect your son or we will take him from you.

After 25 years of caring for someone with autism, including winning a judicial review to ensure funding for his education, Sinead was not too scared by the threat.

‘There is not a court in the land that would do such a thing,’ she replied.

One month later, police turned up on her doorstep with a council official to say that a secret court hearing had empowered the authorities to seize her son Martin.

Pictured: Mother Sinead with son Martin, whose names have been changed to protect their identities for legal reasons. Sinead says her family has spent £200,000 over five years trying to get him back after he was taken into care by social services and moved to a home two counties away where they claim he is 'kept prisoner'

At the same time, social workers arrived at the farm where Martin was enjoying work experience and told him that they needed to take him into safety since his parents were unable to care for him – and then put him in a care home two counties away.

‘I could not believe it,’ Sinead recalled last week. ‘I called my husband Paul, who broke down in tears, and then I collapsed. Our son had been kidnapped by the state and we were powerless to do anything.’

Since then, this couple in their early 60s – both with a lifetime of service on the public sector front line – have been almost bankrupted after spending about £200,000 trying and failing to win their son’s freedom.

They have spent long weeks fighting lonely battles in court against public-funded lawyers and told they can only meet their son if accompanied by minders.

Worst of all, they say they have seen their son decline from being a cheerful soul into a drugged, desperate and despairing prisoner.

Sinead has spoken to us in defiance of draconian gagging orders that threaten her with prison and the seizure of assets. We have changed all the names in this case and cannot even identify the council involved in the saga.

The Mail on Sunday has revealed how hundreds of teenagers and adults have been torn from their families and held against their will for up to 18 years in secretive, secure hospitals and Assessment and Treatment Units (ATUs).

Our exposures have led to five official inquiries after families told how their children were being locked in solitary confinement, fed through hatches like animals, abused and forcibly medicated in places costing the NHS up to £730,000 a year per patient.

Over the past four years alone, more than 40 people with autism or learning disabilities have died inside these secure units.

Yet Sinead’s tragic story suggests the scandal of incarcerated people with autism goes well beyond all those innocent people cruelly trapped in secure health units.

Martin is in ‘supported living’. He lives in a room in a house – funded by benefits – with carers in the community, yet is still held behind locked doors and stopped from returning to his family. At one point, he was prevented from meeting his mother for 17 months.

‘I’m his Mum but I am powerless to protect him,’ said Sinead, struggling to hold back tears. ‘I feel so impotent. I can do nothing despite this outrageous human rights violation.

Martin was taken away from his parents due to a High Court hearing at which the council claimed he was 'at risk' from his mother. The family has spent the last five years in court battles but have been unable to bring him home

'We spent 25 years trying to give him a normal life and ensure he was not segregated – and now look at him, locked up like this. I’m so distraught.’

Unlike many children with autism, Martin thrived at school after an early diagnosis in infancy. ‘I have such fantastic memories of his childhood,’ said Sinead. ‘The schools were fabulous and everyone worked together to help him.’

The problems began when teachers suggested he apply for a further education college to teach him some skills needed for independent living. The nearest one was 90 minutes away, so it was agreed Martin should live near it during the week.

A fight with the local council over funding led to a judicial review, which his parents won – and as a result, they say, social workers began to interfere.

Sinead was appointed Martin’s ‘deputy’ by the Court of Protection, empowering her to manage his affairs. This was challenged unsuccessfully by the local council, and a gruelling 15-month court battle cost the family £25,000.

The council moved to the High Court and held a hearing without notice, at which social workers claimed Martin’s safety was at risk from his mother. This led to his seizure five years ago.

Sinead said her family found itself fighting on their own in court without legal aid against teams of taxpayer-funded lawyers. ‘They would bully us and use legal jargon that goes way over our heads.’

She alleges that her son has deteriorated badly over the past five years. ‘He was a healthy, happy college student who used to play darts in the pub and go to the cinema with his friends – now he is barely able to function.’

These are difficult cases to investigate, with secret court sessions, social workers involved and swirling, serious allegations.

But I have seen notes from council officials confirming Martin has suffered emotional turmoil – ‘reports constantly refer to him crying or being tearful,’ said one internal email.

‘Our stance until now has always been that [Sinead] triggered such behaviour and stress,’ wrote a council lawyer when she was barred from seeing her son. ‘But that cannot possibly be the case at the moment, given he has not had any contact with her.’

Reports by support staff refer to him frequently crying, ‘shouting and screaming’ and asking to return home. ‘I want to go back to mummy and daddy’s,’ records one log in 2016. Another two years later says Martin ‘wants out’ and to ‘go home to mummy and daddy real soon’.

One thing is clear: Sinead and Paul have been driven to despair. She said: ‘What they have done to Martin has broken us on every level, from emotionally to financially. My husband is distraught over losing his son.

'It feels like there is an alternative universe for families if someone has learning disabilities. It is almost like a state round-up and they are not allowed the kind of lives the rest of society takes for normal. We just want him home.’

Terrified mother flees to Poland with her daughters to 'keep them safe' after autistic son is seized by social workers and taken into care where he 'talks of suicide'

A traumatised mother has fled to Poland with her daughters after her teenage son with autism was seized by social workers and taken into care, leaving him with severe weight loss and talking of suicide.

The woman, who cannot be named due to court orders, fears that if she returns to Britain, her daughters – one of whom also has autism – could also be taken away.

‘She is terrified because she can see what has happened to her son,’ said her husband, who has remained in Britain.

The family say they were targeted after falling out with social services during a long struggle to have their son’s condition recognised and for suitable education.

The boy went to a centre for pupils with behavioural problems but was bullied and barely attended school for four years.

Last year, after an interim court order was imposed, the teenager, now 17, was sent into ‘protected placement’ that his family say has left him bored and depressed. He has lost weight and lives in fear of a violent fellow resident.

‘They have torn my family apart. I don’t know when I will get my son back,’ said the father, an Oxford graduate.

‘No one was at risk, no one had been harmed – yet they have been allowed to do this to my family. My son keeps saying he is crushed and dying inside.’