And if I ever stray so far from the beaten track that I don't know where I'm calling from, the satellite navigation display in my car can pinpoint me to the nearest ten feet. Small world? Global village? Those terms are out-of-date - this planet is so compact I can pop it into my pocket. Or so I thought, until I visited a primary school this week where one imaginative class has linked up with children in a Brazilian settlement. This township is not visible on any map - desperate migrants have seized land near an Amazon port called Itaqui, and built shelters from mud, clay and straw. They can get electricity by illegally tapping into the main lines, a dangerous but vital practice. The only water comes from overworked wells, and the nearest schoolhouse is three miles away. Phones? Faxes? Emails? Not a chance - the Brazilian children can communicate with their English friends only by letters brought by charity workers. Messages take weeks and months to arrive. When letters do come, of course, it’s a major event. I was shocked to realise what a big world this still is, and impressed by the work of the charity, Plan International, who can be reached in the UK at 5-6 Underhill St, London (020 7485 6612). We live so fast and so luxuriously in this country, it's easy to lose our sense of proportion. As usual, it takes the children to remind us.