Thousands of business-school students in Britain and abroad are being investigated for cheating. In the latest scandal to hit the worldwide entry test for business schools, the GMAT, up to 6,000 prospective students may have their scores cancelled after buying questions from a rogue website run by a Chinese criminal gang.

The aspiring executives paid the Scoretop.com website $30 (£15) to access real GMAT questions that had been posted on the site by gang members who had recently taken the exam.

Scoretop.com was shut down last month after an FBI investigation. But The Times discovered at least five other sites selling GMAT questions, also known as Jungle Juice questions, or JJs, for as little as £5 each.

One student, called Luckytest, boasted on the BeattheGmat blog: “A Chinese friend gave me the JJs from July 07 to Dec 07. I recognised 17 questions in my exam. Of course, I saved much time and passed the test easily.”

On another site, more than 300 people had posted their e-mail addresses in response to an offer by Gmatblogger to send them JJs.

This is not the first time that candidates have shown a willingness to cheat in the exam, which is taken by 250,000 prospective MBA students each year and used by top business schools as a key part of the application process. In 2003, US federal authorities broke up a ring of six professional impersonators who sat more than 100 GMATs for their clients for fees of $3,000 (£1,500).

To combat the so-called proxy test taking, business schools will now require applicants to undergo a sophisticated palm-vein scan, which takes an infra-red picture of their hands.

The Graduate Management Admission Council, the publisher of the test, said that any student found to have used the internet to access live questions will have their scores cancelled and will not be permitted to take the test again.

“A lot of people went on to Scoretop knowing full well they were gaining access to stolen material,” said Dave Wilson, the council’s president. “If you contributed questions or boasted about using them on the exam you took then you’re in trouble.”

The council was analysing Scoretop’s hard drive and would pass details of cheating students to business schools within weeks, Mr Wilson said.

Anna Farrus, admissions manager at Oxford University’s Saïd Business School, said: “We’re waiting for the council to send us a list.”

She added: “I don’t think any of our applicants are on it but if they were we’d take it very seriously. We’d kick them off the course.

“Ethics in business is fundamental and it has to begin from the admission process. MBA programmes, especially the top ones, are so competitive and, unfortunately, some candidates will do anything to get accepted.”

Ms Farrus said that cheating was such an issue that background checks were now carried out on a quarter of the school’s 1,000 yearly applicants. “This is a growing problem. We’ve even seen some students paying for fake degree certificates online. It’s unbelievable.”

The Graduate Management Admission Council insisted that the advantage gained by using Scoretop or similar sites was almost inconsequential.

The GMAT test uses a computer adaptive format that generates a unique test for every user based on responses to previous questions. “Even if a site is illegally able to obtain some real questions, it is extremely unlikely that a test-taker will see the same questions on the live exam,” said Larry Rudner, the council’s vice-president for research and development.

Business school students are significantly more likely to cheat than their peers in other disciplines, according to Donald McCabe, a Rutgers University professor of management who surveyed more than 200,000 students over 19 years. He said that students would often cite instances of corporations’ “bottom-line mentality” and ethical lapses to justify their own dishonesty.

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