The trial began last August and the accused was convicted in February. The earlier ruling was upheld again in a brief hearing today.

Tan’s wife, Wang Qinghua, told media that she has not been able to speak to her husband, in custody since April 2009, but was able to see him. He appeared to be in high spirits and good health.

The prosecution did not raise the issue of collapsed schools but cited an article Tan wrote on the 4 June 1989 Tiananmen Square massacre. His supporters are certain however that he was convicted for investigating the schools’ collapse.

In the 2008 Sichuan quake, more than 7,000 classrooms crumbled, burying 5,335 pupils under tonnes of rubble, this according to official data.

Tan conducted his own investigation into 64 schools flattened by the 7.9 magnitude quake and estimated that more than 5,600 students died or were missing, adding that the number was incomplete.

Complaints over school construction emerged after the tragedy. Not only did schools collapse, but they also lacked emergency exits, even though nearby government offices and other buildings remained intact. Parents asked for an inquiry, which Beijing readily initially agreed to, but has not released any results.

In Hong Kong, about 40 protesters, representing 18 different groups, marched from Western Police Station to the central government's liaison office this morning to demand his release. In their view, Tan Zouren was jailed only for writing certain articles.

In recent months, many parents of pupils who died in the quake have repeatedly complained that the authorities are blocking the investigation into the collapsed schools by threatening and jailing people.

Artist Ai Weiwei, who has also investigated the pupils’ death, was detained and beaten by police whilst attempting to attend Tan's trial in August.