Former teachers at The Weald School in Billingshurst say the standard of education in England is under threat.
Veronica and Malcolm Peppiatt, who represent the National Union of Teachers (NUT), argue strike action on Wednesday March 26 is the last resort.
But they believe it is the only way to get through to MP Michael Gove, secretary of state for education.
Veronica said morale among teachers is ‘plummeting’.
“Five years after qualifying, two in every five teachers are no longer teaching. On top of that the current system of training teachers is under-recruiting.
“Instead of dealing with this, Michael Gove keeps attacking our teachers, who are forced to strike to defend themselves and education.”
The former teacher outlined six main reasons for industrial action: to ensure every classroom has a qualified teacher; to allow councils to open new schools where they are needed; to make sure any changes to the curriculum are planned; to ensure there are enough teachers and; to get schools to work together to find appropriate funding solutions.
Malcolm said: “School sixth forms and sixth form colleges are facing 20 per cent cuts while £1.7billion has been allocated to wasteful and unnecessary free schools.”
A spokesperson for NUT West Sussex added: “Support for the campaign is stronger than ever amongst teachers in West Sussex - the NUT strike will be solid across the county.
“Increasing shortages of qualified teachers together with a Government encouraging schools to use non-teachers to teach will mean some heads will try to run schools using non-teaching staff.
“This may keep schools open but it will not deliver quality education for students. NUT members don’t like striking but we are willing to lose pay in our campaign to defend a decent education for all students.
“Left to run their course Gove’s policies will mean fewer students taught by qualified teachers and a poorer education for millions of children.”
West Sussex County Council is warning parents about the impending widespread disruption.
Parents are being advised to check with their child’s school to see what impact the action is likely to have and whether the school will be closed or partially closed to some classes.
Decisions about whether to close a school for the day are taken by individual headteachers and governing bodies.
If a school remains open the headteacher and governing body need to check they have appropriate staffing arrangements in place to ensure the safety of pupils.
West Sussex County Council has stressed that the industrial action is the result of a national dispute between the Government and the teaching union and it has no control of the situation locally.