An unusual opinion poll that has correctly predicted the winner in the last four presidential elections has given Democratic challenger Kerry 57% against 43% for Bush.

The Nickelodeon cable channel, better known for programmes Spongebob Squarepants and Jimmy Neutron, conducted Kids Vote, an online survey of almost 400,000 children on Tuesday.

The latest Reuters/Zogby poll shows Bush and Kerry in a dead heat two weeks before the 2 November election. Other polls also show Bush holding a slim lead.

Perfect record

Nickelodeon has organised its poll every election since 1988, and has a 100% record of picking the winner.

Cyma Zarghami, president of Nickelodeon Television, told journalists why the polls have been so accurate to date.

"The Kids Vote seems to work as a good barometer of the actual presidential vote because, developmentally, kids between the ages of two and 11 share the same opinions and outlooks as their parents," she said.

The survey was the final step in a yearlong political awareness campaign on the children's channel.