Growing numbers of primary schools are paying to teach a theme-based international curriculum initially developed for the children of Shell Oil employees.
More than 150 schools in England have joined the International Primary Curriculum network, spending around pound;10,000 to sign up, then a further pound;1,000 annual subscription.
The network, which has its headquarters in London, provides teaching units to more than 200 schools in 43 countries on themes such as "What price progress?" and "Time and Place". The units encourage pupils to be internationally minded, so, for example, one themed on chocolate examines fair trade.
The curriculum was initially developed for 15 English and Dutch-speaking international schools run by Shell Oil, but swiftly attracted interest from other schools.
Martin Skelton, a founding director of the IPC, said that no mention of Shell was made in the curriculum, although the company had provided crucial start-up money and requested that lessons gave pupils a global perspective.
Cross-curricular, theme-based teaching was popular in Britain in the 1970s, but fell out of fashion in the 1990s when it was criticised for leading to "superficial" and "fragmentary" learning.
However, in the past few years, increasing numbers of primary heads have introduced themed lessons and the Qualifications and Curriculum Authority has proposed that schools try a similar approach for key stage 3.
Although the IPC curriculum was completed in 2000, it only began gaining popularity in England's primary schools after 2003, when the Government's Excellence and Enjoyment strategy encouraged them to be more flexible.
Thirty more schools signed up last term to the IPC.
Ofsted inspectors have praised some schools that use the programme, including Prenton primary in the Wirral, where it said the scheme had led to "imaginative links between subjects, which add interest to learning" and improved pupils' independence.
Brendan Doherty, head of Pearl Hyde primary in Coventry, said he bought the IPC curriculum so his teachers could use it as a "jumping-off point" and develop more confidence in going beyond the timetable.