Public sector workers are staging a strike over pensions in what unions say is set to be the biggest walkout for a generation, reports the BBC.
Schools, hospitals, courts and government offices around the UK are among services being disrupted, as more than 1,000 demonstrations take place.
The chancellor urged more talks, saying strikes would not achieve anything.
Unions object to government plans to make their members pay more and work longer to earn their pensions.
The strike is having the following effects:
The Department of Education says it is expecting 13% of state-funded schools in England, including academies and free schools, to open and 13% to be partially open. The status of 16% of schools is unknown
In Scotland, 30 of the 2,700 council-run schools are believed to be open, says local authority body Cosla, while in Wales 80% of schools are shut
Plane arrivals and take-offs at Britain's two biggest airports - Heathrow and Gatwick - are said to be largely unaffected with only a few cancellations of in-bound transatlantic flights to Heathrow
They will have more information when the next shift is due to turn up for work at lunchtime. The ISU has 4,500 members out of a workforce of 6,000.
In Northern Ireland, no bus or train services is operating
Unions estimate about 300,000 public sector workers are on strike in Scotland while 170,000 workers in Wales are taking action
NHS managers say contingency measures have been put in place to protect services such as A&E units, cancer treatment and end-of-life care
In England, the government estimates about 400,000 nurses and healthcare assistants, paramedics, physiotherapists and support staff like cleaners and administrators are joining the action. It says about 60,000 non-urgent operations, out-patient appointments, tests and follow-up appointments have been postponed
In Scotland, at least 3,000 operations and thousands more hospital appointments are affected
Union leaders say although court staff are taking action, the trial of two men accused of killing of teenager Stephen Lawrence will not be disrupted
Ahead of a national march set to take place in London later, four arrests have been made, two for assaulting an officer and two for possession of a weapon.
Eighteen job centers out of over 900 are closed, according to the cabinet office.
Unions say up to two million public sector workers are to take part in the strike but the cabinet office said early indications show significantly less than a third of civil servants were taking strike action.
The government wants most public sector workers to:
Pay more into their pensions
Work for longer
Accept a pension based on a "career average" salary, rather than the current final salary arrangement which many are currently on
The government says the cost of funding public sector pensions is "unsustainable" as people are living longer
Unions say the proposals will leave members paying more and working longer for less
Speaking from Brussels, Chancellor George Osborne told BBC Breakfast: "The strike is not going to achieve anything, it's not going to change anything. It is only going to make our economy weaker and potentially cost jobs."
He said unions should be holding talks with the government to resolve the pension dispute, rather than taking strike action.
He added that without making difficult choices about dealing with the UK's debts the country "would be bankrupt".
Labour leader, Ed Miliband said he had "huge sympathy" for people whose lives are disrupted by the strike.
But he said he was "not going to condemn the dinner ladies, nurses, teachers who have made the decision to go on strike because they feel they have been put in an impossible position by a government that has refused to negotiate properly".
Shadow chancellor, Ed Balls told BBC Breakfast the pensions row should have been resolved by the government.
Liberal Democrat Party president, Tim Farron told the BBC News Channel the unions were wrong to strike because workers on low to middle incomes would get a "better, or certainly no worse" pension when they retire than is currently the case.
Earlier on Tuesday, union leaders reacted angrily to Osborne's Autumn Statement announcements of a public sector pay cap of 1% for two years, as well as bringing forward to 2026 the rise in the state pension age to 67.
Unison's Dave Prentis: ''This is about low paid women saving up six per cent of their salary for their pension''
Unison General Secretary, Dave Prentis told BBC Radio 4's Today Programme that industrial action by his union was rare but public sector workers "were annoyed". Millions of workers - mainly low-paid women - were being unfairly affected by changes to pensions, he said.
Prentis said the last time unions met the Treasury ministers was November 2, adding "this idea that negotiations are continuing is just not true."
However Cabinet Minister, Francis Maude disputed this claim, saying formal discussions with the civil service unions happened on Tuesday and that talks will take place with teaching unions on Thursday and with health unions on Friday.
TUC General Secretary, Brendan Barber said the public sector was "under attack" by the government, adding that the action was justified.
Courts, job centres, driving tests and council services, such as libraries, community centres and refuse collections have been affected by the strike.
German President Christian Wulff arrived Dhaka
November 28, 2011
German President Christian Wulff arrived here Monday on a three-day official visit to Bangladesh for top-level talks and interaction with civil-society groups in Dhaka.
Wulff, who is paying the visit at the invitation of President Zillur Rahman, flew in here to a red-carpet reception at Hazrat Shahjalal International Airport at about 1:10pm.
President Zillur Rahman welcomed the German president at the airport. Foreign Minister Dr Dipu Moni was also present.
On arrival, President Christian Wulff straight drove in a motorcade to Savar to pay homage to the martyred freedom fighters of Bangladesh at the National Mausoleum to begin his three-day tour.
He reached there at 2:15pm, placed a floral wreath at the mausoleum and signed the visitor’s book.
Later, the German President planted a mango sapling on the premises of the mausoleum to mark the occasion of his first bilateral visit to Bangladesh.
State Minister for Liberation War Affairs Captain (retd) Tajul Islam and chiefs of three staffs were present.
The German President is leading an 84-member delegation comprising members of the German parliament, state secretaries of the foreign office and the economics and technology ministry as well as high-level businesspeople.
During the tour, President Wulff will meet President Zillur Rahman, Prime Minister Sheikh Hasina, Foreign Minister Dipu Moni and opposition BNP chairperson Khaleda Zia.
He is also scheduled to visit the University of Dhaka and deliver a speech Monday.
On Tuesday, Wulff will meet a delegation of the civil society and members of different religious communities at Goethe Institute and attend a dinner at Bangabhavan to be hosted in his honor by President Zillur Rahman.
Before flying back for Germany, the German President will go on a river cruise from Postagola Navy ghat Wednesday.
Bangladesh annually exports goods worth about US$1 billion to Germany.
Wulff is the first German head of state to visit Bangladesh since 1986.
