Welwyn Hatfield schools have largely escaped serious disruption from today’s teachers’ strike, although one is open to the sixth-form only.

Despite a National Union of Teachers strike called “to protect pay and working conditions”, every Welwyn Hatfield secondary school is open as usual, except Chancellor’s in Brookmans Park, where only the older pupils will be taught today.

Monk’s Walk School in Welwyn Garden City has warned parents some classes may not have their usual teachers, some off-site activities may be cancelled, and private study may replace lessons for Year 12 pupils.

Mike Harpham, headteacher of Onslow St Audrey’s School in Hatfield, said: “It is business as usual. We have some teachers on strike, but we are pulling together. Another teacher or member of staff will cover for them.”

Adrian Dudley, deputy headteacher of Bishop’s Hatfield Girls’ School, said: “We are unaffected by the strike. The vast majority of lessons are continuing as usual.”

The union’s acting general secretary Kevin Courtney has claimed teachers suffer from a “a workload crisis which is now completely out of hand”, and the education system could “fall apart at the seams”.