Theresa May has been accused of ignoring the plight of up to 120,000 young migrants who must pay £10,000 to avoid her “hostile environment”, after denying the problem existed.

Campaigners have expressed anger after the prime minister told MPs the young people were “not required” to take any action – despite the risk they will be viewed as “illegal” if they cannot secure their status.

She also denied a bill of £10,000, although that is the cost for the requirement to make repeated applications for leave to remain, plus pay an NHS “surcharge” – a process that also takes a full 10 years.

The controversy was raised in the House of Commons, where Ms May rejected warnings of a repeat of the Windrush scandal facing a group who grew up in the UK but “simply cannot afford the paperwork”.

The young people enjoyed full rights and benefits that “put them on an equal footing to their British citizen peers”, the prime minister insisted.

In fact, anyone unable to secure permanent leave to remain must pay higher university fees, is ineligible for student loans and is threatened by the “hostile environment” policy laid bare by the Windrush debacle, critics say.

“The prime minister is ducking the issue and ignoring the plight of these young people,” said Enver Solomon, chief executive of the Just for Kids Law campaign.

“By the age of 18 they have to regularise their status or their world falls apart. They are British apart from not having a piece of paper and they want to become mathematicians, or doctors, or civil servants – to contribute to this country.

Windrush generation: threat of deportation from UK Show all 15 1 /15 Windrush generation: threat of deportation from UK Windrush generation: threat of deportation from UK The ex-troopship 'Empire Windrush' arriving at Tilbury Docks from Jamaica, with 482 Jamaicans on board, emigrating to Britain. Getty Windrush generation: threat of deportation from UK Jamaican immigrants being welcomed by RAF officials from the Colonial Office after the ex-troopship 'Empire Windrush' landed them at Tilbury. PA Windrush generation: threat of deportation from UK Alford Gardner who arrived in Britain in 1948 on the first Windrush ship to dock in Tilbury, Essex, speaking at his home in Leeds PA Windrush generation: threat of deportation from UK Alford Gardner in Leeds shortly after he arrived in Britain in 1948 on the first Windrush ship to dock in Tilbury, Essex PA Windrush generation: threat of deportation from UK Gardner was 22 years old when he boarded the ship in Kingston, Jamaica, with his brother Gladstone before they and hundreds of Caribbean migrants called on to rebuild post-war Britain disembarked the ship in Tilbury Docks PA Windrush generation: threat of deportation from UK Alford Gardner (right), during his RAF service in 1947 PA Windrush generation: threat of deportation from UK The son of Ruth Williams, a Windrush-generation immigrant, wants to the leave the country after threats of deportation. According to his mother, Mr Haynes applied for British citizenship in 2016 but was rejected, despite Ms Williams having lived in the UK almost permanently since arriving from St Vincent and the Grenadines in 1959. Ruth Williams, 75, said she felt "betrayed" by Britain after the Home Office twice turned down applications for her 35-year-old son, Mozi Haynes, to remain in the country. Ms Williams is understood to have cancer and said she relies heavily on her son for support. PA Windrush generation: threat of deportation from UK The British liner 'Empire Windrush' at port in 1954. Getty Windrush generation: threat of deportation from UK Ruth Williams, 75, with her British passport. "I feel betrayed and a second class citizen in my own country," she said. "This makes me so sad and the Home Office must show some compassion. "I am unwell and almost 75, I live on my own and I need my son to stay here. I need my family around me and I can’t face being alone. He has applied to the Home Office and been refused twice." PA Windrush generation: threat of deportation from UK From the top, hopeful Jamaican boxers Charles Smith, Ten Ansel, Essi Reid, John Hazel, Boy Solas and manager Mortimer Martin arrive at Tilbury on the Empire Windrush in the hope of finding work in Britain. Getty Windrush generation: threat of deportation from UK Jamaicans reading a newspaper whilst on board the ex-troopship 'Empire Windrush' bound for Tilbury docks in Essex. Getty Windrush generation: threat of deportation from UK After half a century in Britain, Anthony Bryan decided it was time to go abroad. But the decision set off a nightmare that saw him lose his job, detained twice and almost deported to Jamaica. AFP/Getty Windrush generation: threat of deportation from UK Jamaica-born Anthony Bryan poses outside his home in Edmonton, north London. Now 60 and a grandfather, Bryan thought the issue could be resolved swiftly, as he legally moved to Britain with his family as part of the Windrush generation of Caribbean migrants after World War II. In 1948, the ship Windrush brought the first group of migrants from the West Indies to help rebuild post-war Britain, and many others followed from around the Commonwealth. A 1971 law gave them indefinite leave to remain, but many never formalised their status, often because they were children who came over on their parents' passports and then never applied for their own. AFP/Getty Windrush generation: threat of deportation from UK Three Jamaican immigrants (left to right) John Hazel, a 21-year-old boxer, Harold Wilmot, 32, and John Richards, a 22-year-old carpenter, arriving at Tilbury on board the ex-troopship 'Empire Windrush', smartly dressed in zoot suits and trilby hats. Getty Windrush generation: threat of deportation from UK Newly arrived Jamaican immigrants on board the 'Empire Windrush' at Tilbury in 1948. Getty

“Instead, they find they are treated as international students and have to pay international fees and they cannot get a student loan.”

Ian Blackford, the Scottish National Party’s Westminster leader, who has demanded a meeting with the prime minister after clashing with her over the issue, echoed the criticism.

“This government is guilty of creating a generation of undocumented citizens, without the rights that many of us take for granted – yet the prime minister failed to grasp the issue,” he said.

“We are talking about young people who live here, who have to wait 10 years and pay up to £10,000 to achieve permanent right to remain.

“The prime minister must change her policies which target innocent young people, and I seek to meet with her to resolve this injustice.”

Ms May was put on the spot because of growing anger over the hoops to be jumped through to gain limited leave to remain (LLR) – a stepping stone to indefinite leave to remain.

Young people must apply for LLR no fewer than four times, paying £2,033 every 30 months to fill in a 60-page form. That fee has soared by 148 per cent since 2014.

It is only after four successful LLR applications that a young person is entitled to apply for indefinite leave to remain (£2,389), taking the total cost above £10,000. A year later, they can apply for full citizenship (£1,330).

Mr Solomon added: “We come across situations where one sibling has to go undocumented because their parents, who have paid their taxes, can’t muster the cash for two young people.”

Someone who is classed as undocumented as an adult is also not allowed to work and can be denied non-emergency health treatment – in an echo of the Windrush affair.

However, during prime minister’s questions, Ms May rejected the figure of £10,000 as one “I certainly do not recognise”.

Instead, she argued that young people with indefinite leave to remain had “access to benefits and entitlements which put them on an equal footing to their British citizen peers”.

“So, a grant of British citizenship is not therefore required,” MPs were told.

“Of course, specific exemptions from application fees are provided to several groups with limited means, such as stateless people, victims of modern slavery or domestic abuse, asylum applicants and children who are looked after by a local authority.”

As recently as 2014, before the introduction of the NHS surcharge, meant to ensure migrants meet their health costs, an LLR application cost £601.