Internal documents show the Foreign Office has “indefinitely” paused targeted sanctions against Chinese officials, according to a Conservative former leader.

Sir Iain Duncan Smith, who is among a group of British politicians sanctioned by Beijing, criticised the “terrible” decision after he raised it in the House of Commons.

His concerns were aired as MPs condemned Hong Kong legislators for passing a national security law that grants the government more power to quash dissent.

Conservative MP Sir Iain warned the new law, known as Article 23, will target peaceful protest and those who voice dissent.

Asking an urgent question, he told the Commons: “Since the passing of the national security law in 2020, the people of Hong Kong have endured relentless oppression in contravention of the Sino–British agreement, yet the UK has done very little to hold those responsible to account.

“The US, who were not the ones who signed the agreement, has sanctioned 42 people, including very senior individuals in Hong Kong. The UK has sanctioned none.”

He added: “We now know that internal documents within the department show that the Foreign Office has paused targeted sanctions against Chinese officials in November 2023.

“And I quote from one of those: ‘FCDO has paused consideration of this work indefinitely.’

“I am one of those sanctioned parliamentarians here and I must say that is a terrible decision and flies in the face of the evidence.

“So will the Government now publish these documents and make a statement explaining why they no longer wish to sanction Chinese officials?”

Foreign Office minister Andrew Mitchell said it was “outrageous” Sir Iain and others had been sanctioned but declined to comment on the UK’s approach.

He said: “We do not discuss across the floor of the House our approach to sanctions, but he may rest assured that we are keeping all such matters under regular review.”

Mr Mitchell earlier said the rights and freedoms of Hong Kong residents have been “deliberately eroded” since 2020 as a result of the Beijing-imposed national security law.

He said the new law “continues this pattern” and it will “further damage the rights and freedoms enjoyed throughout Hong Kong”.

Mr Mitchell said the new law is “likely incompatible with international human rights law” and will come into force on Saturday.

He added: “It will enable the authorities to clampdown on freedoms, including of speech, assembly and of the media.

“It will further entrench the culture of self-censorship dominating Hong Kong’s social and political landscape.

“It fails to provide certainty for international organisations, including diplomatic missions, who are operating there.”

Shadow foreign secretary David Lammy described the new security law as “the latest degradation of rights and freedoms of Hong Kong”, adding it was causing “fear and unease” for Hongkongers, foreign nationals and businesses in the city, as well as those with links to Hong Kong abroad.

Mr Lammy also pressed Mr Mitchell on Foreign Secretary Lord Cameron’s record as prime minister, when he promoted a close UK relationship with China.

The Labour frontbencher said: “In his constant absence, can I ask the minister whether the Foreign Secretary accepts that his golden era with China was a strategic mistake which undermined British influence over Hong Kong, set us on a rodeo of inconsistency towards China, and failed to stand up for the UK’s national security interests?

“And whether we can really expect him to deliver the strong, clear-eyed and consistent approach that is clearly needed?”

Mr Mitchell replied: “He asks me about the view of the Foreign Secretary and his long career and understanding of China from his time as prime minister. I think that the Foreign Secretary, if I may say so, has spoken out very clearly on the change that has taken place since the time when he was prime minister and today.”

But Sir Julian Lewis, Conservative chairman of Parliament’s intelligence and security committee, continued to press Mr Mitchell on the “golden era” of relations with China.

Sir Julian said: “Whilst he says things have changed since then, one thing has not changed: Communist China was a totalitarian state then and it is a totalitarian state now. Isn’t it about time that the Foreign and Commonwealth Office learned that lesson?”