The Picc-Vic proposal envisaged joining the two halves of the rail network by constructing new tunnels under the city centre, connecting Manchester's two main railway stations, Piccadilly and Victoria.

[1] The objectives of the Picc-Vic tunnel were threefold: It formed part of a four-phase, long term strategy for GMPTE over 25 years, which included bus priority and an east-west railway network, as well as a light rapid transport system.

In the early 1970s, Britain was facing economic difficulties and the Chancellor of the Exchequer Anthony Barber announced a £500 million reduction in public expenditure.

In August 1973, the Minister for Transport Industries John Peyton rejected the grant application, stating that "there is no room for a project as costly as Picc-Vic before 1975 at the earliest".

The tunnel was to be controlled by British Rail's standard three-aspect colour light signals together with their automatic warning system (AWS).

The exchange had been designated as a nuclear bunker, and while SELNEC planners were aware of this structure, they were unable to mention it publicly as they were forced to sign the Official Secrets Act in 1971.

The initial publicity for the Picc-Vic plan, which was described as "Manchester's tube project", showed an artist's impression of a platform with a train resembling the 1967 Stock, as used on the Victoria line in London.

This proposed type of rolling stock would have been derived from the "PEP" prototypes on the Southern Region, and would have formed part of the same family of EMUs as Class 313, 314, 315, 507 and 508.

The planned twin bore tunnels were intended to be built with a diameter of 18 ft (5.5 m), large enough to accommodate both a main line train type, and the OHLE wires.

The void area had apparently been included in the construction of the shopping centre in the 1970s to enable a link to be built to a new Royal Exchange underground railway station when the planned Picc-Vic tunnel came into service.

[3] In 2019, in the publication Our Prospectus for Rail by regional mayor Andy Burnham, an underground tunnel through Manchester city centre was once again proposed.