More than half of colleges are cutting the number of courses they offer next year as a result of reduced funding, according to a joint trade union survey.
The survey, carried out by the University and College Union (UCU) and the NUT, details some of the cutbacks being made after more than 95 per cent of respondents said that their institutions faced a reduced budget in real terms next year.
A third of the 69 college union representatives surveyed said the cuts were serious and likely to harm teaching significantly. Only a handful believed their college could make the changes without affecting quality in the classroom.
The number of courses was being cut at 55 per cent of colleges, and class sizes were being increased at more than half, the survey found. More than 39 per cent reported that the number of hours taught for each course was also being reduced to save money.
Respondents also detailed the impact of the 75 per cent cut to entitlement funding, which is used to fund tutorial time and extra-curricular activities. More than three-quarters said their colleges were reducing activities such as sport, music, dance and drama, while most were also reducing tutorial time.
More than a third were reducing careers guidance, despite the replacement of the Connexions service with a requirement for individual institutions to arrange their own independent advice for students.
Union representatives also warned that students at more than half of colleges believed the bursaries replacing the education maintenance allowance would be inadequate, and two-thirds believed that recruitment would suffer as a result.
NUT general secretary Christine Blower said: "The impact of not only the real-terms cuts faced by colleges but also the 75 per cent cut in enrichment and tutorial funding is nothing short of devastating. Teachers in this crucial sector face job losses and increased workload while students will be forced out of education by the two-thirds cut in funding for the education maintenance allowance."
Over three-quarters of respondents said the possibility of redundancies among teaching and support staff had been raised, while two-thirds have begun consulting staff about job losses.
A quarter of the union representatives who took part said that their college was refusing to implement recommended national pay awards and another quarter said they were putting restrictions on pay progression. Nearly a third faced increases in working hours.
UCU general secretary Sally Hunt said: "Colleges will no longer be able to offer students the same high-quality learning experience as courses get shorter and class sizes increase.
"The Government can say all it likes about being committed to social mobility, yet the reality doesn't square with the rhetoric.
"As well as cutting funding for institutions, it has removed vital lifelines for college students, such as the education maintenance allowance."
A spokesman for the Department for Business, Innovation and Skills said: "In light of the current fiscal climate it is critical that we focus investment where its impact is maximised.
"Ultimately FE colleges are self-governing, independent organisations and as such, they are responsible for their own terms and conditions, pay and workforce modelling."