The government is on a fresh collision course with public sector workers over its controversial pension reforms after more industrial action was called by civil servants and NHS staff.
The Public and Commercial Services (PCS) union and Unite announced that their members will take action on 10 May, the day after the Queen's Speech, which is expected to include a Parliamentary Bill on the pension changes.
The PCS said the May walkout will kickstart a programme of action, with another strike at the end of June and industrial action across the civil service, health and education sectors.
Co-ordinated, targeted industrial action in employer groups and sectors, national and regional protests and political lobbying will also be held.
The dispute has been raging for well over a year and sparked a strike by more than 1.5 million public sector workers last November.
PCS general secretary Mark Serwotka said: "The ongoing programme of industrial action with other unions we have agreed sends a clear message to government ministers that we do not accept their unnecessary plans to force public servants to pay more and work longer for less in retirement.
"The government must talk to us with the genuine aim of reaching a settlement but if it refuses, we will press ahead with strikes and protests the length and breadth of the country in the coming weeks and months.
"We will continue to show that there is an alternative to this government's cruel and unfair cuts that clearly are not working."
Unite said its 100,000 NHS members, including health visitors, pharmacists and paramedics, face paying an average of £30 a month more for their pensions.
Officials pointed out that the pension reforms came against a backdrop of pay freezes and cuts in the public sector, and the prospect of regional pay being introduced.
National officer Rachael Maskell said: "The government is picking the pockets of health workers by an average of £30 a month in order to pay for pension changes which will see people having to work longer to get less.
"This disgraceful attack comes against a backdrop of pay freezes and the threat of regional pay in the public sector. In the face of continued attacks, health workers will be stepping up their campaign and looking to join other public sector workers in taking action on 10 May."
Unite's health members voted by more than 9-1 to reject the pension changes.
Kevin Courtney, deputy general secretary of the National Union of Teachers (NUT), said: "While the NUT will not be taking action on 10 May, we do offer our support to those unions who are.
"We will be seeking talks with the other unions, including the other teacher unions, who have not signed up to the government's proposals on pensions with a view to agreeing a co-ordinated campaign to defend our pensions.
"Teachers are determined to continue to defend their pension for which there is no evidence to show they are either unaffordable or unsustainable."
The PCS has around 290,000 members in more than 200 government departments and agencies across the UK, while Unite health members work mainly in England and Wales.
Dean Royles, director of the NHS Employers organisation, said: "I know staff feel anxious about changes to pensions but announcements of industrial action will be distressing for patients and confusing for staff.
"Organisations are currently working with staff locally to help them understand how the pension changes affect them.
"After months of debate we owe it to staff to give them a period of reflection, not provoke them into action that will affect the patients they serve every day.
"Employers' priority is to protect the care, safety and dignity of patients."