“I said it was already a dead end to expect to win the case through legal action because there’s little room to manoeuvre thanks to the government’s posture of rejecting the tribunal’s authority over the case,” he recalled. “As a legal professional, all I can say is if you refuse to appear [before a court], you’ll stand little chance of winning.”

The scholar, who requested anonymity, citing fear of repercussions, went on to suggest the government should instead start making plans for the possible aftermath of an unfavourable judgement by the Permanent Court of Arbitration, expected within weeks.

It was the last time he was invited to such a meeting.

“I must have offended those who are keen to toe the line of foreign policy derived from the top leadership,” he said.

Shortly after the seminar, Beijing launched an unprecedented diplomatic offensive to shore up support from the Asia-Pacific region and beyond for its denunciation of the Philippines’ move and the tribunal’s decision to proceed with the case despite China’s opposition.

Over the past three months, dozens of current and retired Chinese diplomats around the world have been busy publishing articles and giving media interviews in a bid to contest the impending ruling, widely expected to go against China. Beijing claims about 60 Asian, European and African nations have expressed at least partial support for China by saying maritime disputes should be resolved peacefully through negotiations. But several nations, including Slovenia and Fiji, were quick to contradict Beijing’s claims, insisting they would not take sides on the issue. Despite China’s commitment under the UN Convention on the Law of the Sea to honour its dispute resolution methods, Beijing has described the case as “an orchestrated show in the guise of law” by the Philippines and its Western supporters with the aim of undermining its sovereignty.

Amid widespread criticism of Beijing’s rejection of the arbitration case, foreign ministry officials chided as “ignorant” those who called on China to show its respect for international law by accepting the tribunal’s ruling.

Analysts said Beijing’s last-ditch effort underlined the high stakes involved in the case, the first time China has been brought to an international court as a respondent in a border dispute since the People’s Republic was founded in 1949.

Professor Ling Bing , an international law expert at the University of Sydney, said it would be the first case in which an international tribunal would decide authoritatively on some of the most important legal issues surrounding the South China Sea disputes.

“From a legal point of view, the award is a game-changer,” he said. “The repeated resort to shrill rhetoric such as ‘ignorant’ or ‘orchestrated show’ does no service for China in its effort to persuade the international community on the justice of its case, but only reinforces the general impression that China is a sore loser.”

Although the ruling is unlikely to alter the balance of power in the region, analysts warned that Beijing’s international image and reputation were at stake and its maritime ambitions would be subject to greater scrutiny.

Citing senior diplomats, several analysts said Beijing admitted privately that it could not afford to appear before the tribunal and lose the case because of rising nationalist sentiment at home.

Separately, foreign ministry officials confided privately that Beijing had thought about recruiting a team of top-flight lawyers to beat the Philippines in court, but discovered the best maritime lawyers had already been hired by rival claimants.

There have been heated discussions among international relations and law experts on the mainland since the Philippines took its overlapping claims with China to the international tribunal in 2013.

Many have questioned the central government’s handling of the case, complaining that politics appears to have been deemed more important than international legal considerations.

They have argued that China should not have absented itself from the highly charged legal proceedings to avoid a likely embarrassing defeat and said that by ­rejecting the case China had given up its right to participate in the ­selection of arbitrators.

Pang Zhongying , an international relations expert at Renmin University in Beijing, expressed concern about the side effects of Beijing’s high-profile diplomatic manoeuvre to seek allies around the world.

“Beijing’s remedial action to break its largely self-induced ­diplomatic isolation indicated a striking departure from its previous polices on the maritime ­disputes,” he said.

“But it remains to be seen if it can turn the tables on international opinion in the West, which generally depicts China as a bully over its expansive claims and ­assertive island-building efforts.”

Pang and several other analysts also questioned the cost and effectiveness of such a desperate diplomatic salvage campaign, which appeared to target mostly small and less developed nations.

James Chieh Hsiung, a professor of politics at New York University, said Beijing’s belated effort to ramp up support while attempting to invalidate and trivialise the impending ruling reflected its lack of confidence in its own claims. “Endeavouring to buttonhole other countries’ support for China’s position, the way Beijing is doing now, will only make people wonder why China should think it necessary to line up support this way,” he said. “The apparent self-doubt only weakens China’s legal claims.”

Legal scholars also called on the government to give up its much-criticised stance of strategic ambiguity over its expansive claims to the disputed waters. Xu Xiaobing, a law professor at Shanghai Jiao Tong University, suggested Beijing should unveil the evidence supporting the so-called “nine-dash line” claims as soon as possible to repel challenges by rival claimants including the Philippines and Vietnam.

Ling said: “In the long run, China must be prepared to present a coherent and convincing case on its South China Sea claims and present the case in international judicial processes.”

He said Beijing’s rejection of the case also went against a decade of increasing participation in such processes, during which China had sought to integrate itself into the international community as a responsible power.

“To view international law and tribunals as inherently inimical to China leads nowhere,” he said. “It is high time for China to take international law seriously as opposed to merely paying lip service to it.”

Several experts said China’s assertiveness on the South China Sea disputes had laid bare the leadership’s growing ambition to become a world power on a par with the United States.

“The arbitration case has exposed the bitter rivalry between American exceptionalism and the so-called rule of law with Chinese characteristics, which essentially means Chinese exceptionalism,” said another mainland legal scholar who requested anonymity due to the sensitivity of the issue.

Quoting an unnamed Southeast Asian diplomat, Bill Hayton, a researcher at Chatham House, said: “China may not yet be a great power but it already seems to have acquired great power autism.”

Many Chinese experts complain that Beijing’s decision-making has long been plagued by a lack of free debate and independent thinking, saying academic freedom has been strangled by political correctness.

The South China Sea issue was a case in point, critics said, with their dissenting views seldom making the headlines in state-controlled Chinese media.

Professor Jerome Cohen, a veteran law expert at New York University, said in a recent speech that in China’s repressive atmosphere it took an act of courage for anyone to differ from the government’s posture of repudiating the tribunal’s impending judgement.

Ling echoed that criticism. “The government must stop treating academics as its handmaids and surrounding itself with yes-men,” he said. “A lack of diverse and dissenting voices may only lead to bad decisions.”