The Conservatives have been told to “stop throwing mud” at the Government over the collapse of the China spying case, as it said ministers could have done nothing to persuade the Crown Prosecution Service to carry on the case.

Home Office minister Dan Jarvis told MPs the Government did not interfere in the case or attempt to make representations to ensure the strength of evidence.

Mr Jarvis asked the Conservatives to clarify what involvement its ministers had when the two men were charged under a Tory government.

The Crown Prosecution Service (CPS) dropped the case against Christopher Cash, a former parliamentary researcher, and Christopher Berry in September, a month before a trial was due to take place.

Both men, who deny wrongdoing, had been accused of passing secrets to Beijing.

Responding to an urgent question in the Commons on Monday, Mr Jarvis said: “There is nothing that the Prime Minister or any other minister could have done at that point, and would have changed what the law and what the policy was under the previous government between 2021 and 2023.”

He continued: “Ultimately it was an entirely independent decision by the CPS to discontinue the case and they have confirmed that they came under no outside pressure to do so.”

He continued: “I gently say to the Opposition front bench they need to stop throwing mud, and start coming to terms with what happened on their watch.”

Conservative shadow home secretary Chris Philp said the Government had weakened evidence against Mr Cash and Mr Berry, by quoting from Labour’s manifesto.

Mr Philp said: “The current Government’s position has been that all the evidence provided related to the last Government’s policy, but we now know that is categorically not true.

“We know from Matt Collins’s third statement from August this year in paragraph eight that he copied and pasted from the Labour manifesto and he stressed the importance the current Government attaches to a positive relationship with China, weakening the evidence compared to 2023, and bringing in current Government policy, contrary to what we have been told in recent weeks.”

In response, Mr Jarvis said: “The Prime Minister has confirmed that no Labour ministers, or special advisers, were involved with the provision of evidence for this case.”

He continued: “The party opposite have refused to confirm if any Conservative ministers or special advisers were involved in the provision of evidence under the previous government.

“I wonder if any of the former ministers here can provide the answers today.”

He added: “I do wonder whether at any point the shadow home secretary and certain members opposite – not all of them but certain members opposite – have considered the need for some humility, to acknowledge their part, that these activities took place on their watch when they were in government and under the legislation of the time.”

MPs have demanded that the Director of Public Prosecutions Stephen Parkinson provide “a fuller explanation for the dropping of charges”, which he blamed on insufficient evidence that China represented a threat to the UK at the time of the alleged offences.

Two parliamentary inquiries will look into the collapsed trial.

Commons Speaker Sir Lindsay Hoyle had said he was taking “specialist legal advice” about the case and the security of MPs.

Sir Lindsay said: “I am, alongside the Lord Speaker, continue to seek advice from officials and specialist legal advice on what further steps might be taken to pursue this issue in other ways.”

Former Conservative leader Sir Iain Duncan Smith said: “I am a sanctioned member of this Parliament.

“I have been spied upon, and I have had a ‘wolf warrior’ from China follow me around and impersonate me around the world very threateningly.”

Wolf warrior is a term used for Chinese supporters.

He asked Mr Jarvis whether he should refer to China as a threat, with the minister saying it was “for the gentleman to choose his own words”.