Starmer has faced pressure over the failed case in recent days, with his Labour administration and the independent prosecutors rowing over why it failed to proceed to trial.

The Crown Prosecution Service said the case collapsed because the government's evidence did not show that China represented a threat to national security at the time of the alleged offences.

Starmer, a former chief state prosecutor himself, has said the government was only able to submit evidence from the time of the alleged offences, which occurred between 2021-2023 when the Conservative party was in power.

He told parliament he would publish "in full" the three statements prepared by deputy national security adviser Matthew Collins for prosecutors.

The CPS, which brings cases in England and Wales, had clarified that it was up to the government whether to publish the witness statements in the case, he said.

"I therefore carefully considered this question this morning, and after legal advice, I have decided to publish the witness statement," he said.

Starmer added that Collins had "faithfully set out the policy of the then-Tory government," which had not formally designated China an "enemy" -- a threshold required to prove the case under the now-replaced Official Secrets Act

He also denied claims, pushed by the Conservatives, now in opposition, that officials privately lobbied for the charges to be dropped over fears a prosecution could prompt China to pull its investment in the UK.

"Under this government, no minister or special adviser played any role in the provision of evidence," added Starmer.

Charges against Christopher Cash, 30, and Christopher Berry, 33, were dropped last month, two years after they were arrested on allegations of collecting information which could be "useful to an enemy".

They had denied the accusations.

Starmer told lawmakers he was "deeply disappointed by the outcome". "We wanted to see prosecutions," he said.

The UK leader has set about trying to improve relations with China, becoming the first British prime minister in six years to meet President Xi Jinping last year.

His government covets Chinese investment to spur a struggling economy. It is also considering whether to allow Beijing to build a sprawling new embassy in London, which has triggered concern among residents and human rights advocates.