Managing a school is tricky if you are spending four days a week teaching and cannot leave your class to answer the phone.
But it is a common experience for headteachers in Shropshire, a mostly rural authority where a third of primary schools have fewer than 100 pupils.
Patricia Jeffries, head of Hadnall CofE primary in Shrewsbury, has been teaching for 80 per cent of her timetable since she started at the school in 1990.
She said that juggling the two roles had become increasingly difficult because of the growing paperwork and monitoring required to lead a school, so she intends to retire this summer, two years early.
"I've been told by inspectors I should do more monitoring, but it is difficult for me to get out of my own classroom," Mrs Jeffries said.
"It's very stressful when you know Ofsted could turn up."
Mrs Jeffries said that she often spent much of her weekends catching up on administrative work, though she occasionally gives herself time to take part in dog obedience contests, "the one thing that keeps me sane".
Jane Bishop, head of Bitterley primary in Ludlow, said her extra workload had meant she had abandoned her hobby of playing violin with the town's orchestra.
She teaches for 70 per cent of her timetable and also frequentlly works at weekends. "It's difficult to have a life - I think I can cope because I'm a single person, but it's not a job I'd recommend to anyone with a family."
Both headteachers said they enjoyed teaching but wished their schools could afford to let them work in the classroom for less than half of their timetables.
An NAHT study suggests that primary schools in Shropshire only receive Pounds 2,364 per pupil, less than half the amount given to schools in some London boroughs.