Its colloquial name was coined in the 1970s by a sub-editor of the Birmingham Evening Mail, Alan Eaglesfield, after he realised that an aerial picture of the complex system of intertwined loops and ramps reminded him of a plate of spaghetti. It provides access to and from the A38 (Tyburn Road), A38 (M) (Aston Expressway), the A5127 (Lichfield Road/Gravelly Hill), and several unclassified local roads.
The junction covers 30 acres (12 hectares), serves 18 routes and includes 4 km (2.5 miles) of slip roads, but only 1 km (0.6 miles) of the M6 itself. Across 5 different levels, it has 559 concrete columns, reaching up to 24.4 metres (80 ft) height. The engineers had to elevate thirteen and a half miles of motorway to accommodate two railway lines, three canals, and two rivers.
Construction started in 1968 and the junction opened in November 1972 by the then environment secretary Peter Walker. In an unusual meeting of old and new transport technology, the pillars supporting the flyovers over the Grand Union Canal had to be carefully placed to enable a horse-drawn canal barge to pass under the interchange without fouling the towing rope. The junction has undergone major repair work several times since, due to the very heavy traffic through the junction, and some alleged cost-saving measures during its construction. In November 2007, a sliproad running from the Tyburn Road onto the Aston Expressway was closed to undergo urgent repair works. Upon inspection, it was found that Spaghetti Junction itself was in need of repair work due to salt and grit weakening the joints in the structure.
Underneath the motorway junction are the meeting points of local roads; the rivers Tame, Rea and the Hockley Brook; electricity lines; gas pipelines; the Cross-City and Walsall railway lines, and Salford Junction where the Grand Union Canal, Birmingham and Fazeley Canal and Tame Valley Canal meet.
Elastica mentioned it in their "Car Song".
Winners on the 1980s revival of ITV talent show New Faces hosted by Marti Caine from the Birmingham Hippodrome were decided by the audience with a gigantic lightboard known as Spaghetti Junction lighting up to a varying degree as the audience pushed buttons.
The Mensa West Midlands newsletter is named 'Spaghetti', after the famous junction.