The child who cannot be charged as he is under the age of 10 was held for possession with intent to supply an unspecified narcotic.
The boy from west Yorkshire was among a raft of kids held on suspicion of drug dealing last year, The Sun reports.
2,380 under-17s were arrested in 36 of 44 forces in England and Wales.
Many were held on suspicion of dealing Class A drugs including heroin and cocaine.
In London, 553 arrests were made – including a 12-year-old suspected cocaine dealer.
The shocking news emerges as county lines drug gangs plague UK.
