Starving orphans are lured with chocolate and money to wear bomb belts or grenade vests, according to a documentary to be shown tonight.
The Dispatches programme also claims children have been trained to use guns and explosive devices in Afghanistan.
There are 224 children in prison after being convicted of plotting attacks. But the Taliban deny the claims.
One former fighter, Neaz, says he was eight when he was kidnapped by the Taliban after his parents were killed in a raid.
He claims he was plied with sweets and given a suicide vest stuffed with grenades. He said: “They made me try it on. The grenades went all around my body and then they offered me the coins (50 Afghanis, about 60p).
“They told me to blow myself up at a checkpoint. I asked what I’d do with the money if I had to blow myself up.
“But they kept encouraging me, telling me that if I did it I would go to heaven.”
He eventually escaped and walked nine miles to turn himself in to police.
Now aged 10, Neaz lives in an orphanage in Lashkar Gah.
Award-winning Afghan film-maker Najibullah Quraishi said: “Thousands of children are being recruited and taught to make bombs or become suicide bombers.
“It is common for 13-year-olds to carry guns. Less than 10% of the population is educated so these children don’t have their own minds, they only have what the mullahs are telling them in the mosques.”