Christopher Cash and Christopher Berry were accused of collecting insider information about UK politics and government policy, and passing it to a Chinese intelligence agent, who then forwarded it to Cai Qi, one of the most senior politicians in China. Cai is often referred to as President Xi Jinping's right-hand man.
Both Mr Cash and Mr Berry completely denied the charge under Section 1 of the Official Secrets Act 1911. The Crown Prosecution Service (CPS) dropped the case against the pair last month after deciding the evidence did not show China was a threat to national security.
The two men met while teaching in China.
Mr Berry stayed behind, but Mr Cash, whose other love was politics, got a job in the House of Commons - first as a researcher and then as the director of the China Research Group, working closely with MPs like Tom Tugendhat, Alicia Kearns and Neil O'Brien.
In a statement released through his solicitor, Cash told the BBC: "I have, for a long time, been concerned by the influence of the Chinese Communist Party (CCP) in the United Kingdom and, prior to these false allegations, was working to inform Parliamentarians and the public about those risks."
