In the east London school where around 360 of the 380 pupils are from a Muslim, Bangladeshi, background, that simple act had unwelcome consequences. "The Bengali children went absolutely crazy," said Mrs Gillespie. "They were already revved up because of the World Cup.
The challenge of integrating faiths in east London is reflected nationwide, the Primary Review interim report indicates.
"Religion is an inescapable element in the cultural melting pot," the report says. "Teachers spoke of the difficulty of balancing inclusion and shared values with respect for different faiths and cultures."
Now Stewart Headlam is taking part in a government-funded links project with St Elizabeth Catholic Primary where children are from white English, African, Afro-Caribbean, South-American and east and west-European families.
The two schools are only a mile apart. But Mrs Gillespie said many of her pupils had never ventured outside the Collingwood estate in Whitechapel which Stewart Headlam serves. "The scheme has broadened their horizons," she said. "They didn't know many people from other communities before."
The Government has provided pound;3 million for three further pilots.
School linking began in 2002 in Bradford, where riots had sparked fears that the increasingly mono-cultural nature of the city's schools was causing different communities to lead parallel, separate lives.