The nurseries are registered under the Children Act to provide 91 places at a time. During a week, they can cater for 245 children, including 90 who attend in the evening. The college also buys places with childminders.
Nearly all students placing children in the facilities are eligible for free childcare, but are asked to contribute towards meal costs.
Hackney estimates that it supports about 300 learners a year, but it is nowhere near enough. When Margaret Hodge, the education and employment minister, visited the college last summer, she was surprised to be told by Ian Ashman, the deputy principal, that there was probably demand from up to 1,000 students.
"We know that in a typical year there are about 150 people who accept the offer of a place on a course and then turn it down because they can't get a childcare place," says Mr Ashman. "There are probably hundreds of others who don't even bother applying for a college place until their children are old enough to go to school."
The value of good childcare is evident in the fact that about 85 per cent of students with childcare places finish their course, while retention among other students is closer to 80 per cent.
Hackney's largest nursery, which can cater for 73 children at a time, is based at its Shoreditch campus. It employs 40 staff, who speak a total of 10 languages, and has classrooms and play areas for children up o 12 years old.
This year, the college received about pound;185,000 from the Further Education Funding Council towards its childcare bill of pound;400,000. It is constantly looking for new sources of funding and new ways to manage its childcare more effectively. One solution may be to iron out peaks and troughs in the timetable, so that demand is spread more evenly.
"Many staff who teach evening classes like to have Friday afternoon or Monday morning off in lieu," says Mr Ashman. "That means in most colleges these periods are less busy and there is less demand for childcare."
The childcare co-ordinator, Adebisi Mohammed, says that planning the provision at the start of each year can be a nightmare. From this summer, Hackney plans to publish its timetables earlier to help students and planners.
Those who complete a course and move on to another generally keep any childcare place they had. Learners who need more time, perhaps for private study, are asked to use slots between 4pm and 6pm. "It's a matter of managing resources in an effective way so that the largest number of people benefit from limited funding," says Ms Mohammed.
Unlike many colleges, Hackney restricts its nursery places to students. Staff must make their own arrangements. Near to the Shoreditch nursery, however, is an Edwardian building, which the college hopes to convert into an early-years excellence centre with 100 places, 10 of which could be reserved for employees.
A survey in 1998 suggested that facilities are more likely to be used by support staff, even though two-thirds of the college's 450 employees are teachers. "There was higher demand among support staff, which reflects the fact they live more locally," says Mr Ashman.