Westfield College teachers strike in observations row
More than 30 teachers from a high school in Sheffield are taking part in a one-day strike in a dispute over classroom observations.
A National Union of Teachers spokesman said 37 members at Westfield Sports College would take part in the action.
He said the disagreement centred around teachers not being told in advance exactly what time observations would take place - in breach of guidelines.
Head teacher Andy Ireland said the school was open, with most teachers in.
He said he expected the majority of the 80 teachers to be at work at the college, which teaches students aged 11 to 16.
The union has planned further action, if the issue is not resolved.
'Difficult to understand'
NUT joint divisional secretary Ben Morris told the BBC: "There are a number of issues in the dispute, some of which are quite complex, but the key is observations of teachers.
"We're not opposed to them, but our guidelines state there should be a maximum of three a year, at an agreed time."
Mr Morris said because the college would not agree in advance to tell teachers what time observations would take place, it was left with no other option but to carry out industrial action.
Mr Ireland said: "It is very difficult to understand the reasons why the NUT objects to the level of lesson observations at Westfield.
"The governors at Westfield feel that three 25-minute observations a year when the teacher knows which day these will occur in advance is not unreasonable and has enabled a vast improvement in the college over the last year."
The NUT said it planned to carry out a further five days of strike action from 12 December if the issue could be not resolved in further talks.