My old sixth form is slowly bleeding to death, like other sixth-form colleges across the country, and all too few people are speaking out about it. Sixth form is not some stop-gap, an interregnum between school and those aspiring for university. For me, like so many others, it was a crucial stepping stone in life.

Ridge Danyers – or Cheadle and Marple College, as it’s now known – is a rather ugly looking sixth form, but it felt like a liberation from the stultifying atmosphere of high school. It once used to be the biggest provider of adult education in Britain, I’m told; the oldest student in my French A-level class was a woman in her 80s called Beryl. There were thriving vocational courses in areas such as health and social care, and training for aspiring footballers. Every Wednesday afternoon was dedicated to “enrichment”, in the form of a creative writing course.

For the first time, I felt genuinely encouraged to think and to explore ideas. I would never have made it to Oxford without it, and I owe the sixth form far more besides.

It is deeply distressing, then, to learn of the government-imposed vandalism of that sixth form. When I was there, a college source tells me, the budget was between £18 and £19m a year. It’s dropped to about half that now, and it could even end up halving again. The college is no longer giving funding per learner, but rather depends on a flat rate. Partly the college’s plight is down to straightforward budget cuts, but the onward march of academisation has a lot to do with it, too.

It is predicted that the number of sixth forms could drop from 93 to just 10 in five years

What was once Britain’s biggest sixth form faces being reduced to the budget of a modest high school, or a large primary school. In the latest tranche of cuts, several compulsory or voluntary redundancies have been announced; subjects such as politics and music have been dropped from my old campus, and performing arts and modern languages like German have been abandoned altogether. BTec vocational qualifications have been scaled back; the enrichment courses are gone, though they intend to reintroduce them despite funding cuts; and the adult education course hangs by a thread. Students are being deprived of a broad, well-rounded curriculum.

Can the sixth form survive as an independent entity? Despite recently winning an award for its outstanding BTec results, there are huge doubts over its future, and it may be forced to merge with Stockport College, which was placed into “administered college status” at the end of 2013 after being deemed “inadequate” across the board. After a reinspection in December 2014 Stockport College was upgraded to “requiring improvement”.

This trashing is part of a national trend. As the Sixth Form Colleges Association has pointed out, the whole sector is “under serious threat”. Academic, vocational and enrichment courses have been cut away across the country, and it is predicted that the number of sixth forms could drop from 93 now to just 10 in five years.

As the IPPR thinktank notes, while funding for five- to 15-year-olds has been protected, funding for 16- to 19-year-olds has not, meaning they get about £1,000 less than high school students and even less than university students. While the government spends more than £4,000 on 16- to 19-year-olds at state schools, the children of the rich spend around £8,000 a term at a public school sixth form.

By the end of this parliament, spending on sixth forms could fall by over 13%, contributing to what the IPPR calls “a continued demise of the sixth-form college as a distinct institution”.

What a terrible attack on the aspirations of young people. If I was at my old sixth form now, could I have ended up successfully competing against far better resourced, privately educated students and made it to Oxford University? I’m not so sure. I had the advantages of a middle-class background: it will be poorer students who will suffer the most.

It must be set against a general trend of an attack on young people, particularly those from working-class homes. Educational aspiration was famously one of the first victims of the coalition when the educational maintenance allowance – a modest sum of money to encourage students to stay in education after 16 – was scrapped. Maintenance grants for poorer students at university were given the chop in Osborne’s recent budget. As Will Hutton points out, the saddling of those aspiring to university with huge debts has provoked a collapse in part-time student numbers in England and Wales, as well as reducing the disposable income of young people – on top of a fall in their wages of about 10% since the crash – making saving for a deposit all but impossible.

One in four young Londoners are growing up in an overcrowded home, with often terrible consequences for health, wellbeing and education; and young people face either joining the 5 million people on the social housing waiting list, being driven into a rip-off, unregulated private rented sector, or despairing over the increasingly unrealisable dream of home ownership.

Low-skilled, low-pay, insecure work beckons for many; and those aspiring for a job in the professions are often expected to work for free – largely impossible without well-heeled parents to support them.

The attacks seem to come daily. Some of us warned that measures initially directed against migrants would inevitably be broadened out. Tightening the availability of tax credits for migrants may now mean the removal of tax credits for all 18-year-olds for four years, punishing the young working poor and young parents in particular.

What joy it is to be young in Conservative Britain. Living standards falling, debt rising, skilled jobs lacking, decent housing unaffordable, education under attack. In much of the postwar period, to be young was to be optimistic: a sense that the future promised to the next generation would inevitably be an improvement on the lot of their parents. But now insecurity defines the future of the young.

The latest – contested – YouGov poll of eligible Labour members and supporters suggests that Jeremy Corbyn’s appeal stretches across the generations and it is no surprise that some of his most passionate supporters are young. Their futures are being stolen from them, and few politicians are prepared to stand their ground. Sixth form colleges used to open doors. What a tragedy that those doors are being slammed so brutally in the faces of today’s students.

• This article was amended on 12 August 2015. An earlier version said Stockport College was placed in administration at the end of 2013. That is not the case. It was placed into “administered college status”. After a reinspection in December 2014 Stockport College was upgraded to “requiring improvement”.