The case also involved allegations the trio had conducted surveillance against Hong Kong activists living in Britain.

Beijing’s foreign ministry office in Hong Kong said on Saturday that Cui Jianchun, the newly appointed commissioner, had met UK Consul General Brian Davidson the day before to exchange views on Sino-British relations.

“Cui made solemn representations regarding the recent arbitrary arrest of Chinese citizens and unreasonable slander of the Hong Kong government by Britain, and urged the British consulate in Hong Kong to play a constructive role in promoting the prosperity and stability of Hong Kong, as well as the healthy and stable development of China-UK relations,” the statement read.

The Chinese embassy in London has earlier warned of a “firm response” if Britain further jeopardises ties after its top diplomat was summoned by the UK foreign office over the spying row.

Exco convenor Ip said the nature of the Hong Kong Economic and Trade Office’s work in London had moved away from lobbying local politicians as official exchanges between the two places weakened.

“A group of anti-China members in [the UK Parliament] and some Hong Kong exiles are causing trouble there, often introducing bills against the city and even calling for sanctions,” the former security minister said in a TV interview.

“The [trade office] must pay attention, probably by gathering intelligence. Such so-called gathering of intelligence means merely paying attention to these developments.”

Ip’s latest remarks marked a shift from her comments on Tuesday, when she said it was “very awkward and shocking” to learn about the accusations because “it was not supposed to be part of [the offices’] work”.

While serving as a commerce official in the 1990s, Ip helped to establish two trade outposts in Singapore and Sydney.

The veteran politician said in her recent TV interview that she recognised the need for the office in London to gather intelligence.

“I believe that each of the consulates based in Hong Kong is gathering intelligence. Some of the intelligence is publicly available, [such as] TV programmes, media and online information,” she said.

“If our personnel are making similar collection efforts at the [trade offices], why would it be against the law? I really do not understand.”

Ip said British prosecutors should present “very solid evidence” at the trio’s coming trial, and believed Hong Kong and central authorities would “vigorously defend our legitimate interests”.

In a separate programme on the same day, former finance chief Henry Tang Ying-yen said he was “very shocked” to learn of the accusations levelled against Yuen.

Tang, who now sits on the standing committee for the Chinese People’s Political Consultative Conference, the nation’s top advisory body, also stressed the important role played by the offices.

“Our trade offices are very important to us, especially for outreach and communication with foreign governments and the outside world. It is an important bridge,” he said.

“The British government must handle any criminal cases fairly … If they handle the case improperly, we will definitely speak out.”

Yuen and the other two suspects were released on bail after appearing at a hearing on Monday, with the case adjourned until next Friday.

Hong Kong authorities have contacted the British consulate in the city to request more information on the case.

According to the last budget, the work of the city’s 14 overseas trade offices is split into three categories: commercial relations, public relations and investment promotion.