Is China serious about ending the trade in tigers and other endangered animals?

The question posed itself last Saturday as I sat at an auction in Beijing watching the hammer go down on cases of spirits and tonics fortified with tiger, rhino horn and pangolin.

Sales of such products are forbidden by Chinese law and international convention, yet even though the event at the Kunlun hotel had been advertised the previous night on state television and flagged up by outraged conservation groups, uniformed police were initially conspicuous by their absence.

The buyers, however, had turned up in droves, or more precisely in Audis and BMWs, for this was a sale aimed very much at the affluent middle class.

Nobody could be mistaken about the contents. The auction house – Googut – had devoted more than a dozen pages in their catalogue to tiger bone wine. Many other liquors up for sale included tiger as a medicinal ingredient to "stave off chills, improve circulation and eliminate fatigue". The starting prices ranged from 5,000 yuan (£500) to 200,000 yuan (£20,000) per case.

On the screen at the front of the hall, a photograph of each item flashed up on the screen and a counter in four currencies clicked upwards as the auctioneer called out bids from the audience.

I watched silently at first, recalling that exactly one year earlier I had been listening to the Chinese prime minister, Wen Jiabao, reaffirm his country's ban on such products at a global tiger summit in St Petersburg. I also knew that overhead two giant pandas were being flown in a chartered plane to Edinburgh zoo, where they would be presented as symbols of China's commitment to conservation.

I decided to reveal that I was a journalist so I could ask the backroom auction staff about the apparent illegality of the items on sale. They told me they were produced before the State Council banned all trade in tiger and rhino horn products in 1993 and are therefore legal. But this was a half truth. The State Council also ordered that older items be sealed and removed from sale. Ahead of the auction, conservation groups raised this issue with the government.

"It doesn't matter whether the tiger bone products are pre-ban or not, their trade is forbidden by the Convention on International Trade in Endangered Species and domestically in all tiger range states," said Grace Ge Gabriel of the International Fund for Animal Welfare.

"Moreover, the sale of tiger products of any kind confuses the public, stimulates market demand and fuels poaching of tigers."

The NGO protest made a difference. On the day of the auction, the security bureau of the State Forestry Administration ordered Googut to halt the auction of tiger bone wine.

But it was only a partial clampdown – and I wonder how seriously it would have been taken if the auctioneers had not realised that there was a reporter present. Up until the moment I revealed I was a journalist, the auctioneer had coasteed through an earlier part of the catalogue, covering cases of spirits (not wine) that contained tiger ingredients.

Once my journalistic identity was known, however, the police arrived and made a show of locking one of the doors. The staff quietly insisted I leave the hall because I was not a buyer. I do not question their right to do so, but I doubt their motives. (I was not the only person watching without a bidders' card and nobody had cared about my presence before I started asking questions). I whispered back that I wanted to stay a few extra minutes so I could be sure that the bidding for tiger wine would be halted, as the authorities had ordered. Three plain clothes security men then flanked my chair and kept nudging me to leave.

I quietly held my ground, guessing they would be reluctant to make a fuss in such upmarket company. Soon after it was clear that I had no intention of moving, one of the backroom staff went to the front and whispered something to the auctioneer. It may have been mere coincidence, but a few minutes later, just as the sale of the tiger wine was due to begin, the auctioneer announced a postponement. There were audible groans among the audience.

"It's a real pity," one man told me as he walked back to his car. "I came here just for the tiger bone wine. It's really good stuff, but I haven't been able to buy any for a long time."

Looking back, the curtailed auction was encouraging and disturbing. Conservationists have rightly praised the government for taking action. But serious questions remain. Why didn't the authorities intervene earlier? Why did the sale of some tiger products go ahead while others were halted? Will the unsold bottles now either be confiscated or will "pre-ban items" be sold on the quiet?

The authorities acknowledge outstanding difficulties with enforcement. "We don't know yet whether the liquor will be taken off the market for good," said an official at the State Forestry Administration, who declined to give her name. "We cannot guarantee that. All I can say is that we are trying to take measures to stop it."

The auction showed that demand is strong, but – more hopefully – the risks to suppliers and middlemen are rising.

Googut staff said they had not yet decided what to do about the tiger wine. When the Guardian posed as a customer and called them, one member of staff said it may be possible to arrange a sale directly from the owner. Another later said this would not be allowed. "Tiger wine causes us too much trouble. I don't think we will sell any after this."

That kind of corporate thinking could make a difference. The chief executive of Googut, Liu Xiaowei and (knowingly or not) the management of Jinjiang International — the company behind the Kunlun hotel – surely have more to lose than to gain through their involvement in an illegal trade that is killing off one of China – and Asia's – best-loved animals. Saving the tiger should be good business sense.