The Treason Trial was a trial in Johannesburg in which 156 people, including Nelson Mandela, were arrested in a raid and accused of treason in South Africa in 1956. The main trial lasted until 1961, when all of the defendants were found not guilty. During the trials, Oliver Tambo left the country and was exiled. Whilst in other European and African countries, he started an organisation which helped bring publicity to the African National Congress's cause in South Africa. Some of the defendants were later convicted in the Rivonia Trial in 1964. Chief Luthuli has said of the Treason Trial:The treason trial must occupy a special place in South African history. That grim pre-dawn raid, deliberately calculated to strike terror into hesitant minds and impress upon the entire nation the determination of the governing clique to stifle all opposition, made one hundred and fifty-six of us, belonging to all the races of our land, into a group of accused facing one of the most serious charges in any legal system. Background On 5 December 1956, the South African Police's Security Branch raided and arrested 140 people from around the country on the charge of treason as they enforced the Suppression of Communism Act. Those not based in Johannesburg were flown there in military aircraft and held in custody until a hearing on 19 December 1956. The raids were follow-ups to those conducted in 1955 and included search warrants to look for documents at 48 anti-government organisations. On 19 December 1956, 153 prisoners were driven to the Johannesburg Drill Hall for a preliminary hearing to examine the state's evidence. Magistrate Frederick Wessels was the presiding judge with J.C. van Niekerk as the state's public prosecutor. An attempt by the prosecutor to proceed with the case was interrupted three times as the noise of 5,000 black South Africans, hoping to attend the case, surrounded the streets of the Drill Hall and sang "Nkosi Sikeleli Afrika". The proceedings had to be halted. The Labour Party in the UK accused the South African Government of intimidating and victimising those opposed to Apartheid, condemning the trial and called South Africa a police state. Resuming on 20 December 1956, the hearing was interrupted again when the defence objected to their clients being behind a wire fence. After an adjournment, it was agreed by the two sides to reduce it to a barrier tall. The prosecutor J.C.