Another Liberal Party functional constituency member was heckled and booed during RTHK's City Forum debate yesterday after he attempted to defend the performance of functional constituency lawmakers and argue merits for the constituencies' preservation. A rowdy young crowd wearing animal masks followed wholesale and retail sector lawmaker Vincent Fang Kang after the debate, chanting that functional constituency lawmakers were worthless. It was a repeat of a scene last month. On March 20, a man wearing a pig mask threw a HK$20 note at Tommy Cheung Yu-yan, a Liberal Party catering sector lawmaker, after he suggested that the statutory minimum wage should be HK$20. The Liberal Party has three members in the Legislative Council who all belong to the functional constituencies. In the forum yesterday, Fang said he did not think the trade-based seats should be abolished and he believed they played a valuable role - although he agreed the vote-based seats should be expanded. Civic Party secretary general Kenneth Chan Ka-lok responded by saying various studies had shown functional constituency lawmakers were often those who attended the least number of meetings, suggested no amendments to government bills and hardly ever made speeches. The South China Morning Post found last year that in the 2008-2009 Legco session, four functional constituency members took less than half the opportunities to record their stand on matters before them. 'I regret to tell you, lawmaker Fang, that when it comes to voting, you are one who is most often absent,' Chan said. Fang replied: 'When it comes to these statistics, everyone should understand that you can see for yourself whether or not a lawmaker has done his job ... The number of times you attend a meeting, or the number of times you vote, does not reflect your sincerity in your work. 'A lot of geographical constituency lawmakers, when it comes to the three minutes of voting, will register their presence and then leave. Does this count as working?' he said. Fang's comment prompted the young crowd to begin chanting that people should turn out and vote in the May 16 by-elections to signal their disapproval of functional constituency lawmakers. Fang said: 'I just want to say, that those who sit in the chamber and press the button to vote - that doesn't mean they can achieve any results.' The merits of functional constituencies have been increasingly under scrutiny in recent weeks as pan-democrats seek to show how both pledges on the Basic Law and social imbalances require the abolition of these trade-based seats. The Civic Party and the League of Social Democrats will attempt to use the by-elections on May 16 as a de facto referendum to measure public support for the abolition of these seats. A rally will be held on Tuesday, and participants are being encouraged to wear yellow to show support for the referendum campaign. Wong Yuk-man, the league's former chairman, said he did not know whether his party's supports were among the crowd, but he welcomed their participation. 'Now, for every Victoria Park angry old man, there's a Victoria Park angry young man,' he said, referring to how it used to be pro-Beijing old men in the 'City Forum' crowd heckling pan-democrats.