Hundreds of thousands of public sector workers have gone on strike across the UK over planned pension changes.
Picket lines have been set up as teaching unions and some of the Public and Commercial Services (PCS) union gather to protest pension changes.
The unions maintain that new government plans will require more work and contributions at reduced pensions. The government says the plans are "fair to taxpayers", and are continuing negotiations with other unions.
"People are going to be scratching their heads, wondering why teachers and some civil servants are going on strike while discussions are still going," Cabinet Office Minister Francis Maude said on BBC One's Breakfast. "It's perfectly reasonable for people to expect to work a bit longer before they start drawing the pension, which will still be among the very best."
PCS General Secretary Mark Serwotka had a different take on the dialogue between the unions and the government. "While they are talking, they are not negotiating," Serwotka told BBC Radio 4's Today.
The Labour leader Ed Miliband said: "Parents and the public have been let down by both the strikers and the government, as they have behaved in reckless and provocative manner."
Walk-outs by the National Union of Teachers, the Association of Teachers and Lecturers and the University and College Union will affect over 12,000 schools in England and Wales.
NUT Deputy General Secretary Kevin Courtney said, "We realise that's very disruptive for parents and we do regret that. We had hoped to reach a settlement before the industrial action, but the government isn't serious about talks."
There had been speculation of the impact this strike would have on air travel. On Wednesday night, some UK Border Agency staff walked out from 1800 BST.
While travellers have been warned that they should expect delays coming into the UK, those leaving the UK will not be affected because departure staff employed by the airport are not taking part in the strike.
Walkouts by others of the PCS's 260,000 members are occurring throughout the UK.
The Maritime and Coastguard Agency has reported walkouts, but assures the public that all stations are "operational and appropriately manned". There are PCS pickets outside the Old Bailey, England's central criminal court, but the courts remain open.
The government said "early signs are that less than half of the PCS Union's own members have decided to take part in today's strikes" and most courts, job centres, and HM Revenue and Customs call centres will avoid closing.
PCS General Secretary Mark Serwotka claimed his members were left with no choice but to take action against the absence of government effort to "compromise on any of the central issues of the strike".
ATL General Secretary Mary Bousted told BBC Breakfast, "We don't want to be on strike, and we wouldn't be on strike if the government had been prepared to do what they say they're going to do now, and that's negotiate."
The government continues to insist that pension reforms are "essential".
"The private sector has had to wake up to the tough realities of pension provision in a rapidly changing world, and the public sector must do the same," British Chambers of Commerce David Frost said. "If the UK is perceived as a country where we have a lot of public sector strikes, then I think investor confidence, perhaps in putting new business into the UK, could be hit."