"Most teachers say they want more professional development," said Dr Smith. "This is a very good way of doing it. Scientists can put current knowledge directly into the classroom."
The nature of the teacher-scientist relationship depends entirely on the teacher. "The scientist is working with the teacher, not the school," said Dr Smith.
Some teachers are looking for enrichment: to be stretched beyond their normal comfort zone. Others might be unsure about performing practical science and are looking for several pointers.
"For the less confident, we typically provide half-a-day's supply cover, then offer planning time between the scientist and the teacher," said Dr Smith. "In 99 per cent of cases, the scientist will end up in the classroom alongside the teacher."
The network which oversees an estimated 60 partnerships, receives pound;40,000 a year from the Gatsby Charitable Trust, but the funding is due to end next year.
Dr Smith, a plant pathologist, has worked with Maxine Woods, a former primary teacher in Norfolk and now head of Quarry Hill junior, in Grays, Essex, for seven years.
She said: "Phil and I hit it off immediately. We shared a general passion for school science. He visits my school about four or five times a year and the children respond positively to having a real scientist in the lesson.
"We balance exploration, demonstration and hands-on practical work for the children. I have taught cell biology to Years 5 and 6, which would not have been possible without Phil's input."