Hundreds of Fujitsu employees went on strike last week in the first ever national walkout at an IT company.
Scores of those on strike over jobs and pay on Friday also demonstrated outside Fujitsu's London headquarters, while others picketed outside Fujitsu offices in Belfast, Manchester, Stevenage, Crewe, Wakefield and Warrington.
The striking workers said the action hit a number of major Fujitsu contracts, including with Marks & Spencer, Vodafone, the Home Office, HM Revenue & Customs, Defra, the Financial Services Authority, and the Post Office.
The news comes at a time of increased tension between IT staff and employers. One thousand HP staff, working on government contracts, last week cancelled a strike after their employer agreed to talks at the eleventh hour.
Friday's Fujitsu strike demonstrated the "depth of anger" among the workforce, who are protesting against 1,000 planned redundancies, a pay freeze, and the proposed closure of a final salary pension scheme, according to trade union Unite. It also represented successful action in an embarrassing week for the union after the high court blocked its attempts to call a 12-day Christmas strike among British Airways cabin crew.
Fujitsu staff had cancelled a previous strike due in November, after the company agreed to talks. This was followed by an offer that Unite members said gave "little guarantee" over their jobs or pay. The staff rejected that offer and Unite called the strike.