Labour has raised fears that pressure from the Trump administration is delaying an announcement on whether a judge-led inquiry will investigate the UK’s involvement in torture and rendition overseas.

The shadow attorney general, Shami Chakrabarti, and shadow foreign secretary, Emily Thornberry, have written to the prime minister expressing concerns that the government has missed its deadline for announcing whether it will hold an inquiry. “We seek urgent clarification as to whether you or any other government official have received representations from the Trump administration on a potential inquiry, and a commitment that under no circumstances will the government’s decision be influenced by pressure from Trump administration officials or the president himself,” they write.

“It has been 17 years since UK officials first became mixed up in war-on-terror era torture and extraordinary rendition.”

A report earlier this year into UK complicity in torture overseas, produced by parliament’s Intelligence and Security Committee (ISC), was deemed “provisional” by its chair, Dominic Grieve. He said that Whitehall’s terms and conditions had left it “unable to conduct an authoritative inquiry”. The ISC found UK intelligence agencies had been complicit in hundreds of incidents of torture and rendition, mainly with the US, in Iraq, Afghanistan and Guantánamo. The Trump administration had demanded that certain information about joint and American operations should be deleted from the final draft of the report, to meet a US security concern. Grieve said that just one word was redacted.

This has prompted speculation that the US is now putting pressure on the UK not to proceed with its inquiry, which would shine light on clandestine CIA operations overseas. “The Trump administration appears to have taken an active interest in British efforts toward accountability for war-on-terror abuses, and US requests for changes to the ISC’s report earlier this year are believed to have delayed the report’s publication,” Chakrabarti and Thornberry write. “It is concerning that the government’s promised announcement on a judge-led inquiry has been similarly delayed, without any adequate explanation.”

A government spokeswoman said: “The government is carefully considering the Intelligence and Security Committee’s reports into detainee mistreatment and rendition issues and will respond formally in due course. Consideration will also be given to the separate calls for another judge-led inquiry.”

Dan Dolan, head of policy at Reprieve, said: “After reports of US interference in MPs’ investigation into UK involvement in torture, the prime minister should confirm she’s not taking cues from a president who has endorsed ‘waterboarding” and a hell of a lot worse’.”