A Hong Kong trade office manager has denied running a spy network in the UK, challenging a prosecution's claim that he worked as a conduit for information about activists and politicians.

A national security trial in Britain that thrust the role of Hong Kong’s overseas trade promotion offices into the global spotlight has heard the defendant deny he was spying on prominent activists from the city and UK politicians on behalf of China. Two years after his arrest, Bill Yuen Chung-biu took to the witness box last week and challenged the prosecution’s claim that he ran a “shadow” policing operation in the country, serving as a conduit for information about the activists while working...