Schools across Lewisham could be closed on Wednesday (March 26) as teachers strike over pay and pensions.
Members of the National Union of Teachers are taking the action, saying government changes will mean they work until they are 68, their pension contributions increase by half and they will be subject to performance related pay.
Lewisham NUT Secretary Martin Powell-Davies predicted large number of school closures in the borough.
He said: "Teachers do not like taking strike action but they are prepared to lose pay to stand up for education. We do apologise for the inconvenience to parents but we hope they will support us."
The Department for Education says the union is causing unnecessary disruption by striking, despite the fact it has agreed to talk with them.
Council websites, along with newsshopper.co.uk, will have details of which schools are affected on the day.