The Victoria line was built to give as many interchanges as possible with Underground and British Rail lines, with, wherever possible, cross-platform connection between different lines heading in the same direction. To this end, at Highbury & Islington the northbound Northern City Line platform was reallocated to the southbound Victoria line to give a direct link between the two southbound platforms; a new northbound platform was constructed for each line; the northbound running NCL tunnel was diverted to its new platform; and the southbound Victoria line tunnel was joined to the old northbound NCL tunnel.