The owner of the Daily Mirror has said it is in talks to buy the owner of the Daily Express and Daily Star.
Trinity Mirror hopes to buy all of the publishing assets of Northern & Shell, which also owns celebrity magazine OK!.
As well as the Mirror titles, Trinity Mirror also publishes the Daily Record, the Sunday People and more than two hundred regional newspapers.
Northern & Shell is owned by Richard Desmond, who paid £125m for the Express titles in 2000.
Trinity Mirror had previously been in talks to take a minority stake in the company.
Northern & Shell currently owns four national newspaper titles – the Daily Express, Sunday Express, Daily Star and Daily Star Sunday. It also publishes celebrity magazines OK!, new! and Star, and has a 50% stake in the Irish Daily Star.
In 2014, Mr Desmond sold Channel 5 to MTV-owner, Viacom for £463m.
With more than 260 titles to its name, Trinity Mirror publishes regional papers throughout the country, including the Manchester Evening News, Birmingham Post and the Reading Post.
In 2015, Trinity acquired rival regional publisher Local World for £220m, which was created and run by former News of the World editor David Montgomery.
Earlier reports suggested Mr Montgomery, who is now a media executive and investor, was planning to create a new deal with private equity firms to takeover Northern & Shell, with Trinity as a minority stakeholder.
Analysis: Amol Rajan, media editor
Fleet Street, as romantics still call it, is facing massive consolidation – and today’s news is the first big sign of that.
Consolidation usually takes place in markets that are over-supplied, where business models are structurally endangered, and cost savings from combining operations have the potential to be enormous.
Britain’s newspapers satisfy all those conditions.
For a reading population of the size that exists in Britain, there are several national newspapers.
Compare it with America for instance, where – ultimately – there are three truly national titles (The Wall Street Journal, Washington Post, and New York Times) for a much bigger population.
Meanwhile, readers are fleeing online, where the internet has turned general daily news into an almost universally available commodity.
As a result, advertisers are following eyeballs into cyberspace.
Huge change is coming to Fleet Street. I’m told several proprietors are in the market for big offers, because they can see where things are headed. Richard Desmond may just be the first very rich man to decide print is yesterday’s news.
In its statement, Trinity Mirror said: “The board of Trinity Mirror notes that it is now in discussions to acquire 100 percent of the publishing assets of Northern & Shell.”
It added that there was no certainty an agreement would be reached, and any deal would need to be approved by Trinity Mirror shareholders.
The Competition Commission may become involved, but the combined readership of the Express and Mirror titles will be around 29% of market share – roughly comparable to the Daily Mail and its Sunday sister, at (23% and 22% respectively.