It's a cold winter day in 2003, and the director of the State Council's Hong Kong and Macau Affairs Office, Liao Hui, is receiving a special guest in Beijing. The visitor is on a mission from Hong Kong chief executive Tung Chee-hwa and has been assigned a special task: to win Beijing's final blessing for a measure initiated by the Hong Kong government.
Tung wants Beijing to allow residents of designated mainland cities to visit Hong Kong as individuals rather than in tour groups on the individual visit scheme to help the economy rebound after severe acute respiratory syndrome.
But the visitor from Hong Kong does not easily get what he wants. As the envoy recalls years later, he is questioned by Liao, who sternly asks: "Once the [tour] restrictions are lifted, it could become a floodgate that is hard to close. Are you sure Hong Kong can manage the influx?"
After a little more discussion, Liao gives his consent and the visitor hurries back to the airport to catch the last flight to Hong Kong, where Tung is anxious to finalise the details.
That excited envoy could hardly have imagined that, little over a decade later, the gift he was so anxious to secure would have developed into a big headache he would have to handle as chief executive. But that's exactly the situation Leung Chun-ying finds himself in.
The question Liao raised with Leung that snowy day remains unsolved and is now even more pressing, despite the benefits Hong Kong has reaped from the individual visit scheme.
With a recent survey showing that 70 per cent of Hongkongers wanted to see the number of mainland tourists capped, Leung gave his clearest hint yet that controls could be imposed, saying his administration was speaking to Beijing on the issue, without offering details. Earlier last month, Beijing's top official on Hong Kong, National People's Congress chairman Zhang Dejiang , told the HKMAO and mainland tourist authorities to work with local officials to "conduct proper studies on Hong Kong's capacity in receiving mainland tourists".
While little has been heard on the study since, Leung admitted last weekend it touched on the "growth and structure" of the tourist influx, adding that his government realised the effect the visitors had on locals' lives.
However, one thing Leung did not mention in public was that the government's talks with mainland authorities were proving far from easy, as they involved officials in many provinces and an array of local interests, rather than one or two ministries in Beijing. There are now 49 cities covered by the individual visit scheme.
In fact, local interests have emerged as a key sticking point for Hong Kong in negotiations with the mainland on many issues, not just tourism. Gone are the days after the handover when local governments on the mainland - willingly or otherwise - easily obeyed instructions from Beijing that tended to favour Hong Kong. This change of attitude among local governments is subtle and natural; their argument is that they must put local people's interests first, just as Hong Kong's government must.
Interestingly, the belief that governments must put local people first is exactly why Hongkongers expect Leung to review and adjust the individual visit scheme. By the same token, provincial governments have their own interests to look after, and seeing Hong Kong consider a curb on visitor numbers may push local governments to consider counter measures aimed at Hong Kong. All of these factors complicate the study.
The reality is this: when Leung visited Beijing in 2003, he had to persuade just one minister to make a top-down decision that local governments would be happy to follow. Now, as Hong Kong seeks to control the influx, the city must take into account the concerns of many counterparts. The top-down approach no longer works well, instead facing local resistance.
Cross-border exchanges can be complicated. Tourism is not, and will not be, the only issue at stake. Garnering a better understanding of each other's interests is the first step towards finding a feasible solution.