Live 8 concerts organised by Bob Geldof to raise awareness of African poverty could become the largest global broadcast as they hope to attract more than 3.9 billion viewers.

Organisers said they were confident they could beat that figure after attracting 140 television networks around the world to show next week's anti-poverty concerts.

They said millions would also watch the likes of U2, Madonna, Stevie Wonder and Sheryl Crow via the internet.