Pupils arrive at Sunnyhill primary from Africa, a local women's refuge and temporary council housing.
But not all stay long. Some classes at the school in Lambeth, south London, lose a quarter of their pupils in 12 months - putting severe strain on teachers, support staff and the budget.
Now ministers are considering a proposal which would provide extra resources for schools, like Sunnyhill, in areas with high pupil mobility.
The plans, set out in a consultation paper on school funding published last month, would come into force in September 2006. They are a recognition of the extra cost of administration, staffing and outside services incurred by schools with high pupil turnovers.
Annie Clews, Sunnyhill headteacher, said: "A teacher organising a class will put up 30 coat pegs, give out 30 maths books and set 30 individual sets of targets. Within a few weeks they are having to replace pegs, give out more books and set another set of targets.
"Children who arrive have often moved school already and have gaps in their education."
The 500-pupil school employs a counsellor, has a fast-track assessment procedure for new arrivals and a system to monitor pupils' progress.
Teachers have to cope with pupils who speak 49 languages other than English and a wide range of abilities.
Mrs Clews is obviously proud that the number of pupils gaining level 5 (one above the expected level) in tests for 11-year-olds is close to the national average. But she is also quick to point out that one 11-year-old arrived two months ago with the literacy and numeracy skills of a six-year-old. She said: "It changes your targets. You have to look at children's progress rather than attainment. We hope he will get to at least level 2 by the time of the tests."
High mobility also makes it more difficult to create a positive atmosphere.
"If you have a group of children who all start at age five and leave at 11, they all learn to get on. If in every year some leave and others arrive, that cohesion is harder to achieve.
"If we are talking about excellence for all then the Government has to provide equality of opportunity. At the moment mobile pupils are not getting a fair deal and neither are their schools," she said.
Consultation on new funding arrangements from 2006-7 is available from www.dfes.gov.ukconsultations. The closing date for responses is May 13