The following sites
can expect disruptions - airports, tax offices, driving test centers, job centers, colleges, military sites and museums.
In spite of the planned strike action, the UK government has made it clear in a speech by the Queen
that these austerity changes will go ahead.
The Immigration Services Union which represents around 4,500 border agency staff, is anticipating walkouts at Heathrow, Gatwick, Stansted and the Eurotunnel.
Public sector unions
will be holding their third one-day walkout in 12 months, which will be led by the health workers at the Unite union, teachers and lecturers at the University and College Union, Public and Commercial Services (PCS) civil servants' union, Nipsa civil servants' union in Northern Ireland and Royal Navy support staff at the RMT Union.
PCS will represent the largest bloc, with 250,000 members, followed by Unite, with 100,000 members, giving a total of more than 400,000 public sector employees on walkout.
Mark Serwotka, PCS general secretary has said that strikes over public sector pensions changes would show that "the tide has turned" against pension reforms.
Last November approximately 1 million public sector works held a national strike, which was followed by a series of agreements for health, education, civil service and local government employees.
Despite opposition to the changes which include changing public sector pension age to the state pension age and higher contributions, these pension reforms were included in the Queen's speech.
Major civil service, health and education unions have not backed these reforms and Serwotka has said that he would urge the Trades Union Congress to reopen negotiations with the government on pensions.
Serwotka spoke before a rally in central London to mark the strikes: "The significance of this strike is that the government clearly thought that 30 November was the end of it, and they are clearly trying to project the image that the issue is done. These strikes will show very clearly that this is not the case."
Taking part in a strike over changes to the teachers' pension scheme will be tens of thousands of lecturers from around 65 universities and colleges and 270 further education colleges.
The changes to the pension scheme would see lecturers paying an additional £350 and £500 a year in pension contributions, which is approximately a 50% increase. If these changes are introduced in 2015, many lecturers will have to work until the age of 67 or 68, instead of the current 65 years.
Sally Hunt, general secretary of the University & College Union (UCU), has said that staff were already feeling the impact of government pension changes. She stated, "It is simply not fair for ordinary families to be to be bearing the brunt of the government's cuts while those at the top get tax cuts."
Around 60,000 lecturers will be involved in the walkout.
In the health sector, Gail Gartmail, Unite assistant general secretary said, "Today's industrial action will build on the high level of anger that was on display during the November 30 strikes."
"This anger has been increased by the Government's hardline insistence that public sector employees work longer, pay more and receive less when they eventually retire."
"Our members believe that the Government is attacking their pensions as a means of helping reduce the budget deficit, which has been caused by a greedy City elite, that has brought the economy to its knees. This is blatantly unfair."
Unite is the union for around 100,000 health staff, which includes health visitors, some paramedics and radiologists.
, despite the planned walkout, ministers have insisted that negotiations with unions will not be reopened.
Cabinet Office minister Francis Maude said: "It is very disappointing that a handful of unions insist on carrying on with futile strike action which will benefit no one."
"Public sector workers are being asked to work a bit longer and pay a bit more, but they will continue to get a guaranteed pension which is index-linked and inflation-proofed."
"Most staff on low and middle incomes will receive a pension at retirement as good as what they expect today, and for many it will be even better."
Those visiting London today should expect some major disruptions.