West Cross Route
This part of Ringway 1 follows the route of the West London Line railway very closely, and it would have been elevated for its entire length from Harlesden to Wandsworth. It was originally planned to have four lanes on each carriageway (perhaps with three through interchanges). However, it was recognised that this would cost a stupendous amount of money to build, and such was the perceived urgency of this road that it was proposed to build it as a dual three-lane elevated motorway, with a space in the centre into which the fourth lane in each direction could then be added relatively easily.
Two studies were conducted into its alignment, both by consulting engineers Husband & Co. Every detail of the road, from its alignment and elevation to its junction layouts, was planned at this stage and it was even known where each supporting pillar would be placed in relation to the railway tracks beneath it. Strangely, though, all information concerning the West Cross Route dries up at the Thames - there are hints that a bridge would be built but almost nothing is known south of there. This suggests that, unlike other sections of Ringway 1, the transition between the West and South Cross Routes was to be made at the river and not at a major interchange.
Continuing from the South Cross Route in Battersea, the motorway would have run on the north-east side of the West London Line railway, crossing the Thames on a new bridge. Once it landed on the North bank, there would have been a large free-flowing interchange with the "Chelsea Embankment Connection", a spur motorway linking to the Chelsea Embankment itself*. The complex interchange (shown right; click to enlarge) adjacent to the former Lots Road Power Station would have been almost entirely elevated, allowing full access between Ringway 1 and the spur, and north-facing access for a smaller single-carriageway link to Townmead Road.
Continuing north from the Chelsea Interchange, the motorway would have run on a viaduct directly above the railway line, with existing street bridges replaced to lift them above the level of the motorway. A short double-bend took the motorway directly behind Earl's Court Exhibition Centre. Today large buildings are on the line of the road, but it's not clear whether the motorway would have been lifted above them or if they didn't exist at the time it was planned.
Still running directly on top of the railway, an interchange with the A4 was planned at West Kensington. Two different designs were proposed here. One would serve only the A4 to the west, with no access to or from Central London, and provision was made for a future radial motorway. This proposal appears to be for the M4 to terminate on the West Cross Route. The alternative was for a three-level stacked roundabout interchange. The original proposal for an enormous saddle-shaped roundabout was changed to a more modest diamond-shaped one. As part of the plan, the A4 would be provided with an underpass under the West Kensington and Warwick Road junctions.
North of the A4, the road would have continued over the West London Line, with the carriageways splitting apart to pass either side of Olympia station. This odd arrangement, with the West London Line in the middle of the elevated motorway, would continue almost until Holland Park Roundabout. Initial proposals for an underpass here (shown left with the final design; click to enlarge) were rejected because of the steepness of the resulting slope between the underpass and elevated viaduct. A flyover was proposed there instead, with the southbound motorway and A3220 sharing an exit from the roundabout, but the northbound having separate entry points to it.
From the Holland Park Roundabout northwards, the motorway was built, running alongside the railway line to an interchange with the A40(M) Westway. This section was built as dual three-lane with a hard shoulder, whereas subsequent engineering reports called for dual four-lane standards on the West Cross Route. As a result this section might well have been widened if the rest of the route had been built.
North of the Westway, the West Cross Route would have swept across yet more of North Kensington, taking out most of the northern half of the severed Latimer Road, and staying close to the West London Line. On reaching Willesden Junction, a large and complex free-flow junction would have completed the circuit by connecting it to the North Cross Route.
The section between the Holland Park Roundabout and A40(M) Westway was the only bit that got built. At its northern end it joins Westway at an elevated roundabout that was obviously built with provision for the northern part of the West Cross Route to plug in: the intended final configuration is shown to the right (click to enlarge).
The existing road is well known by both its title, West Cross Route, and by its former number, M41, which was the most absurdly pompous designation for a mile or so of dual carriageway between two roundabouts. This is the classic example of why the whole of a motorway project should be built, or nothing at all. The M41, as was, dumped all its traffic onto the urban roads of Shepherd's Bush and Kensington, and made the local situation considerably worse. The extension as far as the A4 would have made a difference, but the plug was pulled in the very widespread shock and disgust surrounding the completed Westway.
After the Ringway plan was cancelled, the West Cross Route rose from the dead on more than one occasion. At first it was to be a grade-separated dual carriageway as originally planned, forking into two branches at its southern end to split cross-river traffic between Battersea and Wandsworth Bridges. It kept coming back, scaled down every time, losing its grade separation bit by bit and becoming the "Western Environmental Improvement Route" (WEIR).
At the time the M1 was extended south to its current terminus at the North Circular Road in 1979, space was left for the southward continuation of the motorway. Ringway 1 had long since been cancelled but provision was made anyway, on the very distant hope that it might be extended along the proposed line of Ringway 1 to meet the WEIR. This idea was very short lived, and the last vestiges of the West Cross didn't last much longer. Its final gasp was in 1988, when building the WEIR was part of the recommendments made to the Department of Transport by Halcrow, who had been asked to examine transport in south-west London (more detail is on the R2 Western Link page). When this plan too was scrapped, the WEIR finally vanished down the plughole and hasn't been seen since.
* Hazy plans existed at the time to link the Chelsea Embankment with the Victoria Embankment via a new tunnel bypassing the Houses of Parliament, creating a partially grade-separated riverside expressway.
Diagram of planned interchange between WCR and A40(M) Westway is by Nathaniel Porter.