The latest provision means that the newspaper publisher has put aside a total of £60m to cover costs relating to the scandal, which includes damages payouts and legal fees.
Trinity said it has settled more than 80 per cent of claims, but “the lengthy process of settling claims and the structure and quantum of legal fees for the claimants” has required the provision to be increased.
The group also revealed it has signed a five-year print and distribution deal for The Guardian and Observer newspapers from early 2018.
The announcements were made alongside a trading update for the 26-weeks to 2 July, in which Trinity said revenue is expected to fall by 9 per cent on a like-for-like basis.
Print advertising and circulation revenue fell by 21 per cent and 6 per cent respectively over the period, although Trinity said the decline was impacted by strong comparatives last year when the European Championship took place.
Chief executive Simon Fox said: “The trading environment for print in the first half remained volatile but we remain on course to meet our expectations for the year.
“I anticipate that the second half will show improving revenue momentum as we benefit from initiatives implemented during the first half of the year.”
Trinity Mirror’s titles include the Daily Mirror, Sunday Mirror and Sunday People, as well as regional newspapers.
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