On 6 October, the Rivonia Trialists were formally charged. On 13 June 1964, Mbeki organised a march from Brighton to London, after the Rivonia Trialists were found guilty of high treason. They were expected to be sentenced to death. The students held a night march to 10 Downing Street and handed a petition, signed by 664 staff and students at Sussex University, to the Prime Minister. Thereafter, they held a demonstration outside South Africa House in Trafalgar Square. The next day, London television showed Mbeki leading the march. This kind of lobbying helped the Trialists, who were spared the hangman's noose. For the next three decades, Mbeki would take up the job of rallying support against apartheid. Mbeki completed his bachelor's degree in economics at Sussex University in May 1965. With his own parents unable to attend his graduation ceremony, Adelaide Tambo and Michael Harmel took their place at the event. While in London, Mbeki spent all of his summers with the Tambo family.