The trouble-free entry to Hong Kong of one of the most wanted Tiananmen Square protesters upholds the city's basic human rights and freedoms. But it also serves to underline concerns raised by the denial of entry on the same day to Danish sculptor-activist Jens Galschiot. Twice in little more than a year, decisions by immigration officials have cast a cloud over our tolerance of free speech. Saturday was a politically delicate time for Xiong Yan to set foot on Chinese soil for the first time for 17 years - on the eve of 20th anniversary commemorations of the June 4 crackdown, which fall in the same year as the 60th anniversary of the founding of the People's Republic of China. It is understandable that Mr Xiong worried whether he would be allowed to enter Hong Kong. He remains, after all, personally committed to the fight for democracy in China. And the former student leader did leave the mainland without permission after serving a jail sentence for his part in the protests. But against that it is reasonable to assume that the fact he is no longer so well known, and is now an American national and a US army chaplain, may have worked in his favour. Even with his history, his plan to participate in yesterday's June 4 march and Thursday's vigil, traditionally peaceful events, hardly constituted a threat to society. There was no obvious reason to deny him freedom of speech and movement. This should be reassuring, given that these core values have been put to the test by recent events, such as the denial of entry to eight human-rights activists who intended to protest against China over Tibet at last year's Olympic torch relay. But that makes the denial of entry to Galschiot even more disappointing. It is true that Galschiot was one of those barred last year, when the government feared disturbances and was concerned to see that the relay went smoothly. But on this occasion he planned to do no more than Mr Xiong - participate in the march and vigil. His plans to repair his Pillar of Shame sculpture at the University of Hong Kong and present two more - to the university and the Legislative Council - may have been seen as publicity stunts on a politically sensitive topic. But that hardly infringes the boundaries of free speech. Pressed for an explanation of the different treatment, a government spokesman says the Immigration Department has the power to decide whether to give a passenger permission to land. If Mr Xiong poses no threat to society at this time, how is Galschiot so different that he should be refused entry? That question casts worrying doubt over tolerance of free speech. Only if there are genuine reasons to doubt that people will confine expressions of their views to peaceful protests should they be barred from entering Hong Kong.