Mr Hancock decided not to refer the acquisition of a number of titles from Richard Desmond’s media empire for further investigation.
His decision came after the Competition and Markets Authority (CMA) said the deal would not lead to a substantial reduction of competition in the newspaper market.
In a statement, Mr Hancock said: “I accept the CMA’s findings that whilst it is, or may be, the case that a relevant merger situation has been created, the merger does not give rise to a realistic prospect of a substantial lessening of competition in any market.
“I have also accepted Ofcom’s conclusions that the merger does not raise concerns in relation to plurality of views, nor does it raise concerns in relation to free expression of opinion in newspapers.”
He added: “In light of this, and having considered representations submitted by interested parties in response to the PIIN (public interest intervention notice), I have written to the parties today confirming my decision not to refer the merger for a Phase 2 investigation.”
The CMA now has the final say on the matter and is expected to deliver its decision imminently.
Simon Fox, chief executive of Trinity Mirror, which will change its name to Reach after the acquisition, said: “Today we are two successful separate news organisations, but together we will be stronger and better able to compete and adapt to the challenging conditions in which we operate.”
The acquisition comes at a time when newspaper circulation is in decline and advertisers are moving online.
Trinity Mirror owns more than 240 regional papers, including the Machester Evening News, the Bristol Post and the Daily Record.
The deal gives the company control of four national newspaper titles also including the Sunday Express, Daily Star and Daily Star Sunday, plus celebrity magazines OK!, New! and Star.