Explainer | What is the UK National Security Act used against 3 men, including 2 Hongkongers, in London and how does it compare with domestic legislation?

The arrest of three men, including two Hongkongers, in the UK on spying charges marks the first time people from the city have been held under Britain’s National Security Act.

The central and Hong Kong governments have spoken out over the arrests, accusing the British authorities of “political manipulation” and have also demanded full details of the allegations. The three men are next expected to appear in court on May 24.

The Post, in the run-up to the high-profile trial, takes a closer look at the UK legislation and compares it with Hong Kong laws.

What is the UK’s National Security Act?

The National Security Act passed both houses of the UK parliament in July 2023 and came into force in December that year. It was designed to cover a wide range of areas such as espionage, sabotage, people working for foreign powers and terrorism, with new offences introduced.

Among the new offences were three espionage charges drawn up to replace a series of Official Secrets Acts.

The new offences relate to obtaining or disclosing protected information or trade secrets and assisting a foreign intelligence service.

The UK Home Office said in a fact sheet last year that the offence of assisting a foreign intelligence service would reduce the ability of overseas agencies to carry out “a range of hostile activities against the UK, extending beyond traditional espionage activity”.

Officials said the foreign interference offences were designed to boost the power of police and intelligence agencies to counter state-sponsored actions against the country, as existing criminal charges such as bribery or fraud did not match the scale of the harm caused.