But he feared failing his degree course after he was given a fail mark of 37 per cent for his dissertation.

Professor Andrew Graves told Li at a meeting he could resubmit the 12,000-word essay, appeal against the mark, or accept it and withdraw from the course.

But Li offered a fourth option, the court heard. He told Graves, "I am a businessman", and placed the cash on the table in front of him.

"You can keep the money if you give me a pass mark and I won't bother you again," Li allegedly said.

Shocked, Graves asked Li to leave. But as Li put the money back in his coat a replica handgun loaded with six 22-calibre pellets fell from the pocket to the floor, the court heard.

Judge Michael Longman told Li that the weapon caused fear and alarm to Graves at the meeting on November 23 last year.

"You attempted to persuade a university professor to behave in such a way that if it had been successful you would have undermined the integrity of the universities in the UK and the legitimacy of degrees from universities here, and the University of Bath in particular," Longman said, according to reports inside the court by Press Association.

"Your bid to achieve a pass mark by offering what was a bribe to your professor was ill-conceived to the point of being a spectacular mistake and one which was doomed to fail from the start."

Li pleaded guilty to the charges of bribery and possessing an imitation firearm.

He was sentenced to 12 months in prison and ordered to pay £4,880 in prosecution costs.

Prosecutor Mark Hollier said: "The final part of the course is for students to submit a dissertation of about 12,000 words.

"That had to be in by the first week of September. Mr Li's dissertation was submitted that September last year.

"It was marked by Professor Graves. The pass mark is 40 per cent and the mark awarded was 37 per cent."

Li's dissertation mark was checked by external examiners from University of Oxford and University of Cambridge and found to be correct, Hollier said.

Defence counsel Blake James said Li came from an affluent family in China where his father was a respected government official and businessman.

He said Li was not a "sham student" and had come to Britain in 2006 to undertake a computer science degree course at the University of Bath, which he passed.

Documents showed Li was progressing well in his masters course until he failed the dissertation, James said. At the time of the final module, Li was working for his father's firm - earning £25,000 a year with a bonus of £11,000 - as well as studying.

"When he learned the dissertation result it was a bitter blow to him," James said. "He genuinely felt he had done all right."

James said Li was concerned he would not be able to replace his expiring student visa with a tier-one visa without passing his course. His visa has now expired.

He said Li was used to carrying large amounts of cash with him and had the air pistol, used for shooting practice, in his possession, as did not want to leave it in the car during the meeting.

Li sobbed in court as the sentence was handed down while his parents, wife and parents-in-law sat in the public gallery.

He plans to return to China with his wife, also a University of Bath student, after his release.