More than 2,300 teachers and support staff staged strike action this week to protest against public sector spending cuts and job losses affecting schools.
The strikes organised by the NUT affected more than 120 schools, nurseries and children's centres in London, with marches on town halls also taking place.
The action followed the mass protest organised by the TUC at the weekend, in which an estimated 400,000 people took to the streets to campaign against wider cuts in public spending, which will begin being implemented this week.
NUT members in Camden, north London, and Tower Hamlets in the east of the capital, backed a one-day walkout on Wednesday against jobs cuts and the "damage" being done to special educational needs services and teacher training.
Around 1,500 people from the NUT and Unison, which represents support staff, marched in Tower Hamlets, with about 80 schools in the borough being closed or partially shut, the NUT said. Members were balloted in response to council proposals that the union claims will result in nearly 200 children's services posts disappearing.
In Camden, around 700 teachers took action, with at least five secondary schools and nine primaries being forced to close, the union said. Teachers were balloted after the union claimed that council spending plans would result in #163;20 million being cut from the children's services department.
Alex Kenny, secretary of east London NUT, said that teachers, pupils and schools needed the "high-quality support" they receive from the local council.
"We are not talking about backroom bureaucracy, as David Cameron would have us believe, but essential services that enhance the expertise of teachers and so improve children's education," he said.
And Andrew Baisley, Camden NUT branch secretary, agreed, saying teachers were "deeply concerned" about planned cuts that risk damaging standards of education.
"We have some affluent areas, but also some areas of extreme deprivation and it is those kids who will suffer," he said.
A spokesman for Tower Hamlets Council said the authority understood the "strength of feeling" about the depth of cuts "brought about by government policies".
No libraries, children's centres or school services would be closed as a result of cuts, according to the spokesman. Instead, 500 management jobs would be lost, mainly through voluntary redundancy or early retirement, he said.
A spokesman for Camden Council said the strikes were not because of disputes in any particular school, but about cuts to wider education.
"We understand that NUT members wish to express their concerns, but it is regrettable that students will miss lessons as a result," he said.
The action against cuts follows ongoing industrial disputes in schools in England over plans to seek academy status. NASUWT members are planning strikes next week in at least four schools that want to become academies.