According to Unite, members have taken action because Newsquest has refused to negotiate a potential pay increase for two consecutive years. A 24-hour strike began this morning and will be repeated every Thursday, the union claimed.

Regional officer Norman King said: "Every other publisher has sat down with Unite and discussed pay increases, Newsquest is the only one that is having a two-year wage freeze – due to inflation, that freeze is now a wage cut to our members."

King added that the pay freeze was being implemented, despite the fact that two of Newsquest's titles printed at the plant - the Glasgow Herald and Evening Times – are believed to be making a profit.

Unite members, around 100 of whom are currently on the picket line, were angered further this morning when agency workers were hired to cover the work.

King said: "They would rather pay agency staff to complete the work than sit down and talk to their own employees."

The newspaper industry has been through a tumultuous couple of years, which led to several major publishers, including Johnston Press and Trinity Mirror, to announce pay freezes in 2008 and 2009.

However, last year Trinity paid bonuses to all its staff and pay increases are currently being negotiated across the country.

Newsquest was unavailable for comment.