One of the mainland's biggest events for grass-roots bloggers has been cancelled for the first time in its six-year history because no landlord in Shanghai dared provide a venue for the annual conference, which was scheduled to open today. By yesterday afternoon, at least three landlords who had initially agreed to let out conference rooms or had accepted deposits for venues said they were unable to provide premises for the event. The China Blogger Conference, which began in Shanghai six years ago, was planned for Shanghai Jiao Tong University this year, but organisers had also contacted other institutes, including Shanghai University of Finance and Economics and its service centre for student employment, as back-up options. Conference organisers, who spoke on condition of anonymity, attributed the failure to find a venue to pressure from the authorities, though none had seen any official order banning the conference. One organiser said all universities in Shanghai had been warned not to provide a venue. The website of the China Blogger Conference displayed one sentence in yellow characters over a yellow background yesterday which could not be seen without pressing particular keys. 'The grass mud horse has been harmonised,' it said, in a reference to the central government's policy of fostering 'social harmony'. Many mainland internet users characterise themselves as 'grass mud horses' - a homonym for the phrase **** your mother which internet users have embraced as a symbol of their fight against policies that infringe on personal freedom. A party and reception for people attending the conference at a restaurant today was also cancelled after its organiser was threatened. One organiser said the blogging environment had deteriorated this year. A member of the conference's organising committee had been invited for 'a cup of tea', an informal interrogation by the authorities about their activities, organisers said. But people already in Shanghai, including journalist and blogger Rebecca MacKinnon and Zhou Shuoguang, a citizen journalist and blogger also known as Zuola, still intended to meet informally. One organiser said people who were supposed to attend the conference were in or near Shanghai, waiting to see what would happen. 'All speakers except Yunnan propaganda head Wu Hao will be there.' A committee member said internet researcher Isaac Mao was still trying to get to Shanghai from Hong Kong but was worried that he might be stopped by the authorities. Zeng Jingyan , the wife of jailed HIV/Aids activist Hu Jia , said she had noticed how low-key the organisers were this year in the face of so much pressure. Guangzhou-based lawyer Tang Jingling , who signed up for the conference for the first time, said he was not surprised the Shanghai authorities had cracked down. 'Shanghai has been infamous for being very tough on grass-roots opinions and human rights events,' he said. 'The authorities don't want outspoken writers to get together, possibly coming up with some new ideas.' He said it would become increasingly difficult to host such an event. 'It would be safer to host it in a smaller city close to a big city where the transportation is convenient and at the same time avoid attention from the authorities.' Some of Tang's friends did not sign up because of the uncertainty over the conference's location.