In the week when A-level results are published and students are frantically phoning the Universities and Colleges Admissions Service for a place on a degree course, the go-it-alone tactics of many colleges and universities are adding to their confusion.

Admissions tutors, who get the A-level results up to a week before the students, are anxious to hit recruitment targets in shortage subjects such as science and engineering. They are phoning students at home to guarantee them places with grades lower than those offered by competitors. Some advertise in local papers urging students to apply direct.

UCAS was so concerned that it asked Tony Higgins, its chief exective, to write to all vice-chancellors and principals telling them to stick to the rules.

Poaching has always been recognised as a problem. But it has escalated this year because universities and colleges which fail to hit recruitment targets face stiff financial penalties.

The increasing free-for-all could bring about the eventual collapse of the clearing scheme run by UCAS. New universities, formerly the polytechnics, are said to be the worst offenders.

Mr Higgins’s letter follows complaints that “too many students are being encouraged to apply direct, sometimes on institutions’ own application forms, but sometimes on no forms at all . . .

“Many thousands of students are being admitted to universities and colleges but are not going through the UCAS system.”

The letter continues: “This has been particularly galling to those institutions who follow UCAS rules to the letter but then find students whom they thought would be registered at their institutions failing to turn up.”

FE colleges which offer places to students turned down by universities are hit when the admissions tutors change their minds.

One large college in the north of England estimates that poaching will lose it 90 per cent of its intake for some courses.

The subsequent financial backlash forces colleges to scrap courses, leaving students who thought they had a place stranded.

John Dunford, president of the Secondary Heads Association and UCAS board member, said: “I am concerned that young people leaving our schools may not be getting a fair deal because the admissions system is not working properly. ”

Students who have already signed up for Higher National Diploma engineering courses in FE colleges are a prime target for universities who have failed to recruit suitable students.

FE colleges which offer degree and higher diploma courses are among the hardest hit. Stockport College two years ago lost more than 1,000 students to poachers. Last year staff took steps to discourage students from being tempted away.

Dick Evans, the principal, has warned colleges not to rely on official or ministerial action to save them from the student poachers.

But, he said, for many colleges and an increasing number of schools which have compacts with universities, poaching is beyond their control. “We have a partnership with Manchester University to take students for some of the course. If they are poached from the university we lose the cash.”

Government ministers are known to be concerned about the clearing system. While urging universities to play fair, UCAS wants to avoid tougher measures.

Mr Higgins said: “In our consultation with institutions, UCAS has been asked to draw short of imposing sanctions on institutions, which it knows are abusing the system, preferring corrective measures to be applied either through peer pressure or through my writing direct to the vice-chancellor or principal. ”