The Chinese ambassador has been summoned to the Foreign Office following allegations of “foreign interference on UK soil”.

Lord David Cameron, the Foreign Secretary, ordered the summoning of Ambassador Zheng Zeguang on Tuesday after three men were charged under the National Security Act for allegedly assisting the Hong Kong intelligence service.

Ambassador Zheng met with a senior official at the Foreign Office on Tuesday morning.

A Foreign Office spokesperson said the department had been “unequivocal in setting out that the recent pattern of behaviour directed by China against the UK including cyber attacks, reports of espionage links and the issuing of bounties is not acceptable”.

Chi Leung (Peter) Wai, 38, Matthew Trickett, 37, and Chung Biu Yuen, 63, appeared in court on Monday charged with foreign interference and assisting a foreign intelligence service.

Yuen, also known as Billy Yuen, is a retired Hong Kong police officer who now works as a Hong Kong trade official based in London.

Wai is a UK Border Force officer and Trickett is an Immigration Enforcement officer who served for six years as a Royal Marine.

They are accused of information gathering, hostile surveillance, acts of deception and forcing entry into a UK residential address, with the primary targets of this activity said to be members of the Hong Kong diaspora based in the UK.

The trio did not enter pleas and were bailed until May 24, when they are due to appear at the Old Bailey.

Downing Street said the charges were “deeply concerning” and that the Prime Minister “thanks the police for their work keeping us safe”.

The Prime Minister’s official spokesman added that the UK was “continuously monitoring possible espionage routes” and had taken “unprecedented action” in passing the National Security Act to “deter states from operating against the UK”.

A spokesperson for the Chinese Embassy described the charges as a “fabrication” and an “unwarranted accusation” against Hong Kong.

In March, the Government accused China of conducting a cyber espionage campaign against politicians and the Electoral Commission.

News that the Ministry of Defence had been subject to a cyber attack last week also prompted speculation that Beijing was responsible, but the Government is yet to attribute the attack to a specific actor.

China condemned the UK’s decision to summon Ambassador Zheng, saying in a statement: “During the meeting, Ambassador Zheng made further serious representations to the UK side on the UK’s wrongful behaviour, including its unwarranted accusation against the (Hong Kong) government, and refuted the excuses made by the UK side.

“He was unequivocal that the UK must stop anti-China political manoeuvring and not go further down the dangerous path of jeopardising China-UK relations.”

The statement added: “Ambassador Zheng urged the UK side to immediately correct its wrongdoing, stop interfering in China’s internal affairs, stop spreading lies about so-called ‘China threat’, stop its provocations against China and stop its arbitrary law enforcement against Chinese citizens in the UK.”

In a warning to the Government, the statement added: “We want to make it clear to the UK side: any move to interfere in China’s internal affairs and undermine our interests will be met with a firm response.

“The UK side must not go further down the dangerous path of jeopardising China-UK relations.”