Thousands of Home Office staff, including airport immigration workers, are to stage a 24-hour strike the day before the opening of the Olympics in a row over jobs, pay and other issues.
The Public and Commercial Services Union (PCS) said its members will walk out on 26 July and will take other industrial action, such as a ban on overtime, between 27 July and 20 August.
The action will hit border controls at ports and airports including Heathrow, threatening disruption to people travelling to the Games.
The union warned it will announce further action if ministers continue to “refuse” to negotiate an agreement, warning that job and spending cuts are hitting services to the public.
PCS general secretary Mark Serwotka said: “The lives of staff have been made intolerable by these cuts, and they’re at breaking point.
“Ministers have known about these issues for a very long time and need to act now to sort out the chaos they have caused.”
Home Secretary Theresa May branded the PCS strike decision “shameful”. She said: “They are holding a strike on what is one of the key days for people coming in for the Olympic Games. We will of course put contingency arrangements in place to ensure we can deal with people coming through the border as smoothly as possible.”
Earlier, Labour leader Ed Miliband said: “People should not be disrupting the Olympic Games.” Prime Minister David Cameron also condemned the strike, insisting the Olympics would be safe and secure regardless of any industrial action.
The PCS is in dispute with the Home Office on several issues, including plans to cut 8,500 jobs, the threat of compulsory redundancies in the passport office in South Wales, pay rises capped at 1 per cent following a two-year wage freeze, privatisation of services and alleged victimisation of union representatives.