He said Mr Cheng offered to provide Barbados lilies to a wholesaler at a price that was about 20 times less than the market rate. The wholesaler than gave Mr Cheng a receipt for the order, which was never filled.

The receipt was later used as the basis for compensation to farmers for the Kowloon-Canton Railway Corporation land acquisition.

Mr Chan, whose flower farm was affected by the West Rail, said because of the misquoted price, he was offered only about HK$200,000 instead of HK$19 million.

Assisted by the Democratic Party, Mr Chan urged the board to overturn decision by the privacy commissioner for personal data not to ask the KCRC to release the receipt Mr Cheng obtained from the wholesaler.

'When Mr Cheng [later] came to assess our crops, we all thought he was employed by the KCRC,' said Mr Chan. 'He was also said to be a land manager of the KCRC ... on the Legislative Council paper.'

The KCRC said that Mr Cheng was employed by a surveying company named Chesterton Petty, which was commissioned by the corporation for land resumption. The KCRC also said it had no personal data regarding Mr Cheng and did not acknowledge possessing any document involving the Barbados lilies.

Appeal board deputy chairman Ambrose Ho SC said it was not the board's job to determine the identity of Mr Cheng, but whether the privacy commissioner should act on Mr Chan's complaint over the receipt.

Wilson Lee, acting for the commissioner, said the receipt did not mention Mr Chan, therefore he did not qualify as a relevant complainant. But Mr Chan argued that the receipt had deeply affected his financial interests.

Mr Chan said after the hearing that even if the appeal application was rejected, he would continue to seek an explanation from the KCRC.

Mr Ho adjourned the ruling until later this week.