As a first stage, a Preliminary Report was prepared in November of that year into the investigations which had been carried out into the proposal for an extension as far as Little Stanney. At this point, it would connect with the proposed extension of the Ellesmere Port Motorway M531.

It was envisaged that, in due course, it would be extended further to cross the proposed Dee Barrage. Until this was constructed, however, M56 traffic would cross the Dee at either Queensferry or via the proposed Chester Southerly By-pass.

In August 1969, a second Report was prepared justifying the extension as far as Dunkirk, on A5117, at a point between the A41 and A540 junctions. It was considered that the improvement of the existing route was not practicable due to the nearby extensive oil refineries, pipelines, and a recently constructed sewage treatment works. It had been built across peat deposits and subsidence was still evident.

The statutory procedures which were commenced in 1973 were in respect of proposals for

1. the completion of the Hapsford Interchange by the addition of west facing slip roads

2. dual three-lane carriageways from Hapsford to Stoak,

3. the M56/M531 Stoak Interchange, and

4. dual two-lane carriageways from Stoak to Dunkirk.

The Public Inquiry which was held in January/February 1974 also examined the proposals of the Cheshire County Council to extend M531 southwards to the A56 at Hoole Village.

Following a favourable decision, three separate Contracts were awarded. In March 1978 work began on the construction of i) the three mile long section of motorway between Hapsford and Stoak, which included two overbridges and an underbridge at the crossing of the River Gowy and ii) the Stoak Interchange which included lengths of side and link road, and seven bridges over the Chester to Ellesmere Port Canal and the link roads.

In the flood plain of the River Gowy, a large quantity of peat was removed and replaced by sandstone from a quarry which was opened-up specifically for the purpose.

Progress on the Interchange Contract was severely affected by the effect of labour disputes, such that the period for completion over ran by 34 weeks.

M56 Lea-by-Backford to Hapsford (J16 to J14)Under the third Contract, the construction of the remaining two mile length of motorway, between Stoak Interchange and the A5117, began in September 1978. It included bridges to carry the motorway over the A41 and the Chester to Birkenhead Railway. A third bridge was required to carry the A5032 over the motorway.

The Contractor took up the option of submitting an alternative tender based on the construction of the carriageways in concrete using the 'slip-form' method. This was the only section of the M56 to have this form of construction. In the relatively short length involved, the concreting was completed within 9 days.

The delay in the completion of the Stoak Interchange prevented the opening of the length of the motorway, beyond Hapsford. However, by March 1981, the whole of the 35 miles of the M56 from Lea by Backford through to the junction with the M63 (M60) at Sharston had been completed, and was in use.