The government's widening access policy is being undermined by persistent concerns about the quality of teaching on higher education courses delivered through further education colleges.
Further education colleges are at the forefront of expansion plans, increasingly delivering validated degree courses and sub-degree courses such as the new foundation degree.
But Quality Assurance Agency director of subject review Peter Milton said that the current round of teaching quality assessments had raised "concerns about quality and standards in a minority of further education courses".
The Department for Education and Skills confirmed this week that almost 10 per cent of subject reviews in colleges lead to demands for action plans.
Another senior QAA source agreed that ministers were worried about colleges' performance. He said this largely explained the decision to subject them to tougher inspections than universities.
The only two failures reported so far in the final round of old-style teaching quality assessments this year are college courses.
Last month Soundwell College in Bristol failed an inspection of its three higher-level courses in business and tourism, with a score of 13 out of 24. This week Herefordshire College of Technology failed an inspection of business and tourism courses, including two degree courses validated by the University of Wales.
The QAA, which gave the college 14 out of 24, said there were "serious defects in the internal quality management processes which have resulted in a failure to identify significant weaknesses in the BA programmes". Two other colleges have been compelled to produce action plans to redress shortcomings after inspections.
Mr Milton said that the concerns about standards in colleges were "demonstrated by the results from the current cycle of subject reviews". Former QAA chief executive John Randall said in his 2000 annual report that a regrettable number of failures in colleges "in some cases must give rise to a question of whether the college has the capacity to deliver such programmes."
However, some commentators believe the colleges suffer from prejudice and in-built disadvantages. Most reviewers are from universities and are unfamiliar with college culture; colleges get penalised for having fewer resources; and colleges are unfamiliar with the methodology.
More than 200 colleges that have never faced QAA inspection before have been scrutinised since 1999-2000. Mr Milton said that "a worrying lack of knowledge about the method prevails among further education staff".
A DFES spokeswoman said: "The QAA reviews have reported some isolated cases of weaknesses in teaching and learning... Colleges are making a significant contribution to the government's aim of increasing and widening participation in higher education."