Cambridge University - where just 28% of applications result in an offer - has admitted it is growing 'desperate' for more applicants to its computer science courses.

Applications to study the subject have dramatically dropped since the start of the decade. In 2000, 500 students applied and 100 were accepted. Last year, 210 applied and 70 were accepted.

The prestigious department is launching a publicity campaign to try to attract students up and down the UK, and is building a website that aims to bust popular myths about computer science.

Professors in the department - the oldest of its kind in the world - say unless they increase efforts to recruit, the "situation will become desperate" and it will be difficult to maintain quality.

They blame dropping numbers of applications on the "geeky" image of computer science and the misconception that all graduate jobs in the field are based in China and India.

Professor Andy Hopper, head of Cambridge's computer laboratory, which runs the course, said: "We don't portray ourselves to potential applicants in a contemporary way. We don't show that computer science knowledge can help solve some of the world's global problems. And we should."

Hopper believes students are still deterred by the burst of the dotcom bubble early this decade, when shares in the internet sector rapidly rose then suddenly plummeted.

"We want potential students to know that the burst of the bubble is well and truly over. There is a shortage of computer scientists in this country, jobs to be filled and the chance to get rich," he said.

This summer a company set up by Cambridge computer science graduates-turned-lecturers, XenSource, was sold for $500m (£238m).

Blueprints for the world's first computers were drawn up at Cambridge by Charles Babbage in the 19th century.

Jack Lang, an affiliated lecturer at the lab, said: "People seem to think computer science is for nerds and for boys playing shoot-em-up games. It's just not true. Not only that, they assume computer science is just about spreadsheets. In fact, it is a subject that is ubiquitous in modern life. It is the basis on which planes are controlled, our bank accounts are guarded from identity fraud and the NHS is kept running."

Professor Peter Robinson, deputy head of the lab, said teenagers should not confuse computer science with IT when looking at university courses. "Ours is a rigorous and demanding course that produces graduates able to both manage and innovate," he said.

Outside Cambridge, the forecast for student recruitment in computer science courses across the UK is at best patchy. Applications fell by 42% between 2001 and 2004, from 29,014 to 16,801. In 2007, they rose by 0.1%.

Dr Mike Rodd, the British Computer Society's director of external relations, describes the national picture as "of great concern". "We think students assume all the graduate jobs in this sector are outsourced to China and India. In fact, there are more vacancies in this country than ever before," he said.

Computer scientists are smiling in one department, though. This month the University of Southampton announced a 20% increase in students for its computer science course - its biggest for five years.

Dr Paul Garratt, the course admissions tutor, puts the success down to integrating electronics into computer science. "Students now are interested in how iPods and DVD players work; that is electronic devices with in-built software and hardware," he said.