Institutional racism is rife in further education colleges, according to a report by a group which trains the sector's leaders.
The influential Centre for Excellence in Leadership (CEL) makes the allegation in a strategy document to be published at its annual conference in April.
The centre highlights a paucity of black and ethnic-minority staff in college management posts, from which the next generation of black principals is likely be drawn. Its report says there are fewer than 60 black and ethnic-minority second-tier senior managers in general further education colleges across England.
The number of third-tier managers - those reporting directly to a senior management team member - is around 200, it maintains.
"It is likely this under-representation is due to institutional discrimination, whether unintentional or overt," the CEL says.
Of England's 375 FE and sixth-form colleges, only five have black and ethnic-minority principals. The Learning and Skills Council has set a target of nine to be in place by 2010.
The CEL was set up in October 2003 to "improve the standard of leadership and the diversity of the talent pool of leaders in the learning and skills sector".
Last year, it encompassed the Black Leadership Initiative, which for two years existed separately to develop black managers in colleges through professional development and mentoring.
In its report, entitled Leading Change in Diversity and Equality, the centre says: "Under-representation suggests that individuals have been denied support in achieving career progression, and accessing personal and professional development, and this is often an issue of power."
Deborah Persaud, the CEL's project manager with responsibility for improving equality and diversity, said: "The phrase institutional racism is emotive, but it is about time we were a bit more honest about the realities in the sector.
"We tend to use that type of terminology with the most extreme cases of bad practice, but actually that term is very good at describing the most subtle angles of discrimination, and it should be used more often."
Ms Persaud called on colleges to have more open and accountable recruitment procedures, and for their appraisal systems to be more transparent.
She also said colleges should have their staff equality and diversity procedures scrutinised at inspection. "Inspection reports comment on inclusion in relation to learners, then why not the workforce?" she asked.
The CEL report says it is not just on race issues that discrimination exists, but bias is also prevalent in relation to gender, disability, sexual orientation, religion, age, working patterns, and socio-economic background.
"It is very important we do not forget about other areas of under-representation," she said. "Only 26 per cent of college principals are women. It would be nice if the statistics across the board matched the census statistics."
Peter Pendle, general secretary of the Association for College Management, said: "It is appalling that there are only five or six black principals in all of the colleges in England.
"We do accept there are very serious problems with discrimination in the sector. We are concerned that many of the second and third-tier managers are in business support posts rather than academic posts, from where principals are generally drawn.
"We are in this position as a result of unintentional institutional discrimination. Though we are starting from a very low base, the work being done is a step in the right direction."