Two men, including a former parliamentary researcher, pleaded not guilty at a London court on Friday to charges of spying for China.
Christopher Cash, 29, and Christopher Berry, 32, were charged in April under the UK's counter-espionage Official Secrets Act.
Both denied the accusations during a hearing at the Old Bailey court.
Cash previously worked at the UK parliament as a researcher, where he had contact with senior Conservative members of parliament.
He is accused of having "obtained, collected, recorded, published or communicated to any other person articles, notes, documents or information which were calculated to be, might be, or were intended to be, directly or indirectly, useful to an enemy".
He is alleged to have committed the offence between January 2022 and February last year.
Berry, who held various teaching posts in China starting in 2015, is accused of the same offence between December 2021 and February 2023.
Authorities in Beijing have dismissed the charges against both as an attempt to "smear and suppress" China.
The trial is expected to begin in around a year's time, with both suspects currently free on conditional bail.