New rules may be needed if public transport firms follow the example of Kowloon Motor Bus (KMB) and refuse to allow advertisements that refer to the Chief Executive, according to a Democratic Party politician. Lee Wing-tat and Wong Bing-kuen, who are running in New Territories West, decided yesterday to ask Citybus, New World First Bus, New World First Ferry, the Mass Transit Railway Corporation (MTRC) and the Kowloon-Canton Railway Corporation (KCRC) to place their advertisement, which includes the question: 'Do you want Tung Chee-hwa to have another term?' KMB was accused of political censorship after it rejected a request on Thursday to carry the advertisement on its buses. The Democrats were told it was because the advertisement was too 'sensitive'. Mr Lee, who demonstrated outside KMB headquarters in Lai Chi Kok yesterday, said he deplored the 'self-censorship' of the corporation. KMB had made the Chief Executive a taboo subject, he said. 'My advertisement is just a neutral political topic. But it now seems that we can't debate Mr Tung. To what extent can it be prohibited?' Mr Lee said a code of practice governing advertising for such firms might be needed. He said he was considering taking KMB and its advertising agent, Top Result Promotion, to court for breach of contract and to ask for compensation. KMB said it would review its policy, but had to abide by its contract with Top Result, while MTRC spokeswoman Stella Lam Lai-yee said Mr Lee's request was being dealt with, and a KCRC spokesman said it did not vet its adverts for political content. A First Bus spokesman said advertisements would be accepted provided they were not illegal, obscene, gambling-related or personal attacks.