If you ask people what was the greatest engineering achievement to come out of 20th-Century Britain, you would get many answers. Some would suggest the majestic Titanic, others may cite the evocative Great Western Castle and King express steam locomotives. Aviation fans will sing the praises of the Spitfire and of Concorde. Perhaps some others would recite tales of the Humber Bridge and Tower 42. Maybe, just maybe, if you asked the right people, they would give you the name of the Worsley Braided Interchange.

So What is it?

Mentioned in the Guinness Book of World Records as the widest section of road in Great Britain¹, it is a series of junctions linking the M60, M61, A580 and A666 in Greater Manchester. It was designed to provide a set of free-flowing routes between these roads, without the need for traffic lights or roundabouts.

This may not have worked out quite as planned. In the mornings, it is not uncommon for Manchester-bound traffic on the M61 to jam up for four or five miles. There are a few reasons for this. First, the M60 around that area is generally very congested, especially between Worsley and the junction for the M62 and M66. Another is that Manchester-bound traffic is dumped onto the A580 East Lancs Road, which already brings in traffic from Merseyside and Wigan, and, being a suburban road, is littered with traffic lights, and can't take the extra traffic. A third reason is that another motorway, the M601, planned to take traffic from north Manchester straight into the city centre, was never built. This might well have eased the congestion.

The Mystery of the A666

The A666 starts in Salford, from the same junction where the A580 joins the A6. Its route goes north through the suburbs of Salford, having a junction with the M60, before hitting the Bolton suburb of Kearsley. At a roundabout in Kearsley, the route of the A666 drops down onto St Peter's Way, a dual carriageway that runs through the heart of Bolton. The question is, which road is the dual carriageway that runs from that roundabout to the M61?

According to older maps, this route is the A666(M), a motorway-grade A Road; this designation was not to last, however. Current road signs do not give this road a name; it is signed as (A666) which means 'leading to the A666'. It is possible that this is either a spur of the M61 or it is the A666(M) with road numbers removed. Some atlases have this marked as the A666; however, the road signs disagree with that.

A further, even more confusing possibility is that the A666(M) runs all the way from St Peter's Way to the M60, with the route of the M61 just joining the A580. It should be said that the reasoning behind these conjectures are conversations for a rainy night over a few pints of Dark Mild, and not for this Entry.

Linkage

The Interchange links these routes:

• Clockwise (Northbound) M60
  • Northbound M61
  • Northbound A666
• Anticlockwise (Southbound) M60
  • Northbound M61
  • Northbound A666
  • Westbound A580
• Southbound M61
  • Northbound M60
  • Southbound M60
  • Northbound A666
  • Eastbound A580
• Southbound A666(M)?
  • Northbound M60
  • Southbound M60
  • Eastbound A580
• Eastbound A580
  • Northbound M60
• Westbound A580
  • Northbound M61
  • Northbound A666

As well as for the sheer number of lanes, the Worsley Braided Interchange is known for its tunnels. When the engineers were originally planning the road, they wanted long bridges to carry some of the slip roads diagonally over the main carriageway of the M61. The engineering technology at the time made bridges of such scale far too expensive to contemplate, so instead they built tunnels for the M61, and laid the slip roads over them.

It is situated between the Salford suburbs of Worsley and Walkden and the Bolton suburbs of Kearsley and Farnworth.

Sample Drives

To best describe the interchange, we'll say what you see when you drive the road.

Northbound on the M60 heading to the M61

The northbound (clockwise) M60 doesn't have a junction with the A580. Instead you should leave at Junction 13 and follow the A575. After the motorway has crossed the A580, two sets of slip roads can be seen to the left of the carriageway. The nearest is the link from the eastbound A580, which joins the northbound M60 further up. The second is the link from the westbound A580 which joins the M61.

Two lanes of traffic split off the M60. If you are travelling into Bolton along the A666, it is best to be in the right-hand lane. These two lanes split from the M60 just as it crosses the A6. They join up with the two lanes from the anti-clockwise M60 to form a four-lane carriageway. This now enters a tunnel as the slip road from the A666 towards the A580 crosses over. Because the road crosses at an angle, the tunnels on the two carriageways of the M61 are staggered. If you plan on using the A666, you should move to the outside (right-hand) two lanes, otherwise stay on the left-hand side.

After the M61 passes under a very long and very bleak footbridge, it splits. The two right-hand lanes form the A666² towards Bolton and Blackburn. Here we have a bit of fun with road names. The A666 runs from Salford to Kearsley before forming the Kearsley bypass, which then runs as a dual carriageway all the way into Bolton. Since the A666 runs continuously from its start to its end, it suggests that the section of road that runs from the M61 to the junction with the single carriageway A666 and the start of the Kearsley bypass can't be the A666. It is certainly marked on most maps as being a motorway. At various points in its existence it has been referred to as a spur of the M61 or as the A666(M). Neither map books nor county councils can decide, so this bit of road remains numberless.

If you are continuing on the M61, it passes under the link road from the A580 towards the A666, the A580 link road having split. It then joins up with the rest of the A580 link road and heads north towards the delights of Chorley, Horwich and Preston.

Southbound on the M61 heading to the A580

The southbound lanes of the M61 cross the A666(M?) just after junction 3. The spur to the A580 splits from the M60-bound traffic here. It joins with the spur from the A666 just after the long, lonely footbridge. The spur road then turns right, crossing over the M61, and runs parallel to the M60, southbound, as it crosses the A6. The spur then dives under the M60, joining onto the A580 East Lancs Road, heading into Manchester.

How it was Built

When construction started in 1966, Kearsley Moss, where the junction is situated, was an empty wasteland. It was fortunate for a motorway junction of such scale that such a massive area of land was not used for either housing, industry or agriculture. This was because Kearsley Moss was a mixture of moss-land and deep peat bogs, undercut by old mining tunnels.

Outfall sewers were built to drain water from the land. 1.5 million cubic yards of peat were removed, and tipped on adjoining land to allow it to be used for agriculture. In total, 4.5 million cubic yards of filling material was imported. Some of the core of the motorway support was made from 160,000 cubic yards of dumped toxic waste that had been polluting the water table of the area. It was encased in clay so it couldn't leach out.

The construction, which was opened in 1970, includes 26 bridges as well as other large engineering works.