Using a series of alias names and different internet accounts, Turner also chatted to 11-year-old ‘Lucy’ for six months and ‘Louise’, who also said she was underage, for a week.
During the conversations he used graphic sexual terms and asked for indecent photographs of the girls.
But Newcastle Crown Court heard the teen profiles were all decoy accounts that had been set up by Guardians of the North.
The Guardians of the North is a Sunderland based organisation whose members pose as children online to snare paedophiles.
After the year long undercover operation, members of the group filmed the moment Turner, a former council worker, was finally led away by officers and put into the back of a police van during darkness.
Footage shows one member of the group tell Turner: ‘You thought you could outsmart the Guardians, not this time.’
Another told him: ‘You’ve tortured me for a full year in these chats.
‘I hope you rot.’
The group tell him ‘tara’, ‘goodbye’ as he is put into the vehicle.
He denied two charges of attempting to cause or incite a child to engage in sexual activity and three of attempting to engage in sexual communication with a child during a trial but was convicted by a jury of all charges.
Turner, 67, from Gateshead, has now been jailed for six years.
He has to sign the sex offenders register and abide by a sexual harm prevention order for life.
Judge Edward Bindloss told him: ‘Three girls were put at risk, one for a long period and one was only 11.
‘The risk of harm here to those three girls, had they existed, is high.’
The court heard Turner has never been in trouble before or since and is in poor health.