The decision of former Home Secretary David Blunkett that there was no serious risk of persecution of those sent back to Bangladesh was irrational, Justice Wilson said at London's High Court on Thursday.
He ruled that the inclusion of Bangladesh on a list of countries - known as the "white list" - which presented no serious risk of persecution was unlawful.
"I hold that whether in July 2003, when it was added to the list, or at any time since then, no rational decision maker could have been satisfied that there was in general in Bangladesh no serious risk of persecution of persons entitled to reside there," he said.
Wilson said the decision to include Bangladesh on the list was made by Blunkett after he had seen reports which highlighted serious human rights abuses, pervasive violence in politics, corruption, torture, child abuse and systematic oppression of religious minorities.
"...no rational decision maker could have been satisfied that there was in general in Bangladesh no serious risk of persecution of persons entitled to reside there"
London High Court
It was clear that persecution and human rights abuses were not isolated problems at the margins of life that the government had argued in court that they were, the judge said.
He gave the Home Office (interior ministry) leave to appeal.
The ruling came as part of a case in which Bangladeshi asylum seeker Zakir Husan challenged Blunkett's rejection of his application.
Amnesty International's report on Bangladesh last year said torture remained widespread in the country during 2003, with at least 13 deaths in custody.
It said police used unnecessary or disproportionate force against demonstrators, over 130 people were sentenced to death, and that rape and other violence against women was widely reported. The government denies wrongdoing.