The Cabinet Office is examining the commissioning of a report that made false claims about journalists who were investigating Labour Together, the thinktank closely linked to Keir Starmer, a cabinet minister has said.

Liz Kendall, the science and technology secretary, indicated it would not be a formal inquiry, as demanded by the Conservatives and some Labour MPs, noting that the trade association for the PR industry was carrying out such an investigation.

The standards committee of the Public Relations and Communications Association is examining a report compiled by the PR consultancy Apco Worldwide into the “sourcing, funding and origins” of a November 2023 Sunday Times report about Labour Together.

The research was paid for and subsequently reviewed by Josh Simons, who was director of Labour Together and is now a Labour MP and Cabinet Office minister, according to sources and documents seen by the Guardian.

“It’s absolutely right that the relevant regulatory body that covers public affairs is already investigating this,” Kendall told BBC Radio 4’s Today programme. “The Cabinet Office will be establishing the facts.”

Asked if this was a formal investigation, Kendall hinted this was not the case, saying: “Establishing the facts is the first thing that you’ve got to do on anything, isn’t it? If you want to look into something properly, you have to be able to establish the facts.”

She added: “The freedom of the press, difficult though it is, is an essential part of the proper functioning of a parliamentary democracy, and that’s extremely important.”

The Conservatives have written to Labour’s chair, Anna Turley, calling for an immediate investigation into Simons’ role and that of other directors of Labour Together, including serving cabinet ministers.

Labour Together, also formerly headed by Morgan McSweeney, Starmer’s recently departed chief of staff, is the thinktank viewed as central to the Starmer project, and to revamping the party after the Jeremy Corbyn period.

The Sunday Times reported that the contents of Apco’s investigation were shared informally with Labour figures in 2024, including present cabinet ministers and special advisers. The report contained allegations about Gabriel Pogrund and Harry Yorke, journalists at the paper, which then spread around Westminster.

The paper reported that Tom Harper, Apco’s senior director and a former Sunday Times employee, wrote that he had examined the “sourcing, funding and origins of the Sunday Times story” using documents and “discreet human source inquiries”.

Harper was said to have made “baseless claims” that the emails underpinning the published story were likely to have come from a suspected Kremlin hack of the Electoral Commission.

“The likeliest culprit is the Russian state, or proxies of the Russian state,” he reportedly wrote. Apco’s report was also said to have referred to Pogrund’s Jewish background and made baseless allegations about his faith, upbringing and personal and professional relationships.

Asked if Simons’ position in government remained tenable, Kendall said: “He is rightly welcoming the investigation that is taking place into this by the public affairs regulatory body. That is right.

“I believe that these issues are essential to protecting the freedom of our democracy, the freedom of our press. And I’m sure you’ll be hearing more about this in the weeks to come.”

Simons has said in a statement: “I was surprised and shocked to read the report extended beyond the contract by including unnecessary information on Gabriel Pogrund.”

Simons said he had asked for the information to be removed before passing the report to the intelligence agency GCHQ. No other British journalists were investigated in any document he or Labour Together ever received, he added.