The need for a high standard modern road south of the River Mersey between the Merseyside and Manchester Conurbations was foreseen many years ago. Such a road was included in the Chapman Plan for Cheshire published in 1947, and the County Development Plan of 1958 defined a line agreed between the County Council and the Ministry Transport.
At its eastern end the proposed road was to be an extension of Princess Parkway, in the City of Manchester, and was included in the proposals of the South East Lancashire and North East Cheshire Conurbation (SELNEC) Authorities published in 1962. It would be part of the local motorway system and complementary to the network of national motorways of which the M6 is the principal north-south route west of the Pennines.
The main functions of the proposed road were to:-
1. Provide an improved means of communication between North Wales and the Wirral part of the Merseyside Connurbation, and the Manchester Conurbation.
2. Cater for the development of industry in North Cheshire.
3. Connect both conurbations to the M6.
The County Council was of the view that it should be independent of the existing road system and grade separated throughout.
In November, 1963, the Minister of Transport announced the inclusion of the Extension of Princes Parkway through to Bowdon in the Trunk Road Programme for 1967-1968. In the following year the Helsby-Frodsham By-pass Section at the western end of the route was also included in this programme, but a date was not specified.
The early work on route location and preliminary design was carried out by the County Council, and was fully described in 'The Blue Report' dated January 1965.
In locating a line of the proposed road, the following main issues were considered:-
1. Between Hapsford and Preston Brook, the alternatives of, a) a 'Marsh' crossing through deep peat deposits and, b) a 'Hill' route across attractive countryside necessitating steep gradients and rock excavation
2. The crossing of the River Weaver, and the Weaver navigation
3. The effect on the development of Runcorn New Town
4. The need for a connection to the Runcorn-Widnes Bridge
5. The interchange with the M6
6. The future connection to the proposed Sale By-pass
7. The provision of a link to Manchester Airport
In April 1967, the scheme became the responsibility of the North West Road Construction Unit, with the Cheshire Sub-Unit undertaking the design and supervision of construction.
A traffic study, undertaken by the County Council, had shown that, within four years, the A56 through Helsby and Frodsham would be carrying more than three times its capacity. Over 30% of the daily traffic flow between Hapsford and Daresbury consisted of medium and heavy goods vehicles.
There was strong support from local action groups for immediate progress being made on the scheme, On one occasion, the car in which the then Prime Minister, Sir Alec Douglas Home, was travelling on the A56, was stopped in Helsby. Irate residents demanded the early construction of a By-pass of Helsby and Frodsham.
The sketch plan below shows the sections described in the summaries of the M56, related to their current junction numbers.