The deal to buy GMG Regional Media, which is worth around £44.8m, is expected to be completed on 28 March, with £37.4m of the cost coming from the release of a long-term print contract.
Trinity will acquire two regional businesses, MEN Media and Surrey and Berkshire Media (S&B Media). MEN Media publishes titles in the North West of England, including the Manchester Evening News.
Twenty-two MEN titles are already printed at Trinity Mirror's Oldham facility. As the contract to print the titles will become redundant, the value of the contract will count against the overall amount Trinity will pay.
S&B Media publishes 10 titles in the South of England, including the Surrey Advertiser and the Reading Post. The titles are printed at the Guardian's facility in Reading, which will be taken over by Trinity as part of the deal. It is understood that printing of the titles will remain at the site.
Two of S&B's other local newspapers in Woking will not be acquired.
Sly Bailey, Trinity chief executive, said: "GMG Regional Media is a perfect strategic fit for our group. This acquisition extends our reach across print and online and is a further step towards our strategic goal of creating a multimedia business of real scale."
The division broke even in the 12 months to December 2009 and has gross assets of £8.7m.
GMG Regional's chief executive Mark Dodson will leave the business. David Sharrock, who is currently chief operating officer, has been appointed as managing director of MEN Media, replacing Ruth Spratt, who is also set to leave the company.
S&B Media will be managed as part of Trinity Mirror's existing publishing business in the South of England.
Carolyn McCall, chief executive of Guardian Media Group, said: "The Manchester Evening News and its sister titles have made a huge contribution to the fortunes of the group for the best part of a century. GMG would like to pay tribute to all the staff for their hard work and achievement in a sector dealing with structural change, as well as economic downturn.
"GMG is mandated to secure the future of the Guardian in perpetuity, and we have a strong portfolio, which has to be in the right shape to achieve that goal. The group board and the Scott Trust [owner of GMG] have made the decision to sell in light of these strategic objectives. We are confident that this decision is in the best long-term interests of the regional business and its staff."
