The Daily Star alleges the contestant is an ex-detective constable "who played a key role" on the Jimmy Savile abuse inquiry.
We are aware of reports concerning the proposed media appearance of a former detective constable.We have been in contact with Channel 5 and made them fully aware of potential risks and their responsibility to live investigations.
All officers joining the MPS and leaving the MPS are required to sign the Official Secrets Act.
More top news
The letter was signed by the CBI, British Chambers of Commerce, the EEF, the Institute of Directors and the Federation of Small Businesses.
A spokesperson said Rory Stewart's remarks were in line with the British government’s stated position.
The minister's intervention will come a week after Trump decertified the landmark agreement claiming it was not in the US national interest.