A man has been jailed for 15 years after making plans, police said, to rape the children of what he thought was a mother chatting to him online.Over the web, Christopher Brand, 62, from Birmingham, discussed going to a location outside the city at a weekend.But the other party was really an officer from an organised crime unit.Brand was convicted of two counts of attempting or facilitating the commission of a sex offence against a child.He admitted obscene publication and at Birmingham Crown Court was sentenced to 15 years with a further six on extended licence.Brand had previous convictions for arranging to meet a child for sexual activity and for possessing indecent images of children, West Midlands Police said.