Ten people have been charged over "a large scale plot to smuggle drugs and phones" into prisons across England.
The eight men and two women, all from the West Midlands, have been charged with three counts of conspiracy to supply drugs, psychoactive substances and banned items.
West Midlands Police said it carried out raids at addresses in Birmingham and the Black Country on Wednesday.
The force alleges the group used drones to drop the contraband consignments.
Police said phones and Sim cards were dropped using drones between April 2016 and June last year.
The eight men, aged between 20 and 43, and two women aged 34 and 40, were arrested from addresses in Coseley, Tipton, Dudley, Oldbury, Weoley Castle, Northfield and Minworth.
It is alleged the group used drones to fly drugs into the following prisons:
- HMP Birmingham
- HMP Oakwood in West Yorkshire
- HMP Hewell in Worcestershire
- HMP Risley in Warrington
- HMP Wymott in Lancashire
- HMP Liverpool
Det Insp Erica Field said: "These arrests are clearly very significant and come on the back of a detailed and very complex investigation into the smuggling of drugs and contraband to serving prisoners.
"Much of the violence behind bars is linked to drug use and supply so it's vitally important we do all we can to cut off the supply lines - and anyone convicted of supplying banned substances into prisons can soon expect to be inmates themselves."
Prisons minister Rory Stewart said fighting criminal gangs is "at the heart of our work in the Ministry of Justice".
"Drug-free prisons are vital to the effective rehabilitation of offenders and the protection of the public," he said.
At Birmingham Magistrates' Court earlier, the ten were committed to appear at Birmingham Crown Court on 12 April and granted unconditional bail.