The move to headship can cut teachers off from the pupils, but James Walker, head of Henry Fawcett school in Lambeth, east London, is still active in the classroom. He mostly takes Year 6, but does on occasion cover in the nursery, which he enjoys.
"Young children are very tactile. In the nursery, they'll sit on your lap - they don't distinguish between teacher and parent; they don't care whether or not it's appropriate," he says.
But he does not agree with banning contact between male teacher and child.
"To deprive children of physical affection is a crime," he says. "They will become lesser human beings if denied physical contact."
The school policy is always to have a witness, and to let female staff take the children to the toilet.
James gained his teaching degree in the late 1970s but did not enter the profession until 1990. Instead, he went into politics, eventually standing as a parliamentary candidate for Labour. He has no doubt about which calling he prefers.
"The frustration with politics is that you do things second-hand and are distanced from reality - whereas in this job you can help children on a daily basis," he says. "There is no more rewarding job than primary teaching. You get so much feedback from the children. A lot of them are from disadvantaged backgrounds and it's very moving to be able to give them a life-chance."