The deal with Trinity Mirror means brands, agencies and repro houses can now deliver advertising directly to every regional title in the UK through the Specle ad portal.
Gordon Davidson, divisional operations director at Trinity Mirror, said: "We are opening up a number of delivery channels for both our national and regional titles in order to give our customers as wide a choice as possible when it comes to delivering ads into Trinity Mirror."
Specle is only the second company, after Adfast, to achieve 100% UK regional coverage.
Scott Ryan, IT director at Accord Holdings, one of the UK's largest regional advertisers, said: "We have been very pleased working with Specle in terms of adding Specle as Accord's preferred partner for automated ad delivery.
"The flexibility of their platform and the approach they have taken is significantly better for us as an agency than any other of the available solutions. Working with their experienced team has helped ensure a smooth transition. Trinity Mirror's direct connection with Specle is great for us."