|Length:||13.5 miles (21.7 km)|
|Meets:||A311, A313, A305, A316, A314, A244, A315, A30, A4, M4, A437, A4020, A4180, A40, A4090, A4005, A404|
|Old route now:||A437|
|Route outline (key)|
The A312 could have had greatness thrust upon it, and parts of it are of a surprisingly high standard. Early plans for the Motorway Box included a north-south route crossing the Thames near Hampton, and passing to the east of Heathrow Airport. The plan was never completed, a route running west of the airport being chosen instead, but some improvements on the A312 axis were made.
Hampton - Harrow
Nevertheless, the route starts plainly enough at a set of traffic lights on the A311 Hampton High Street. That the A312 has ambitions to travel further than most local roads is evident from its name - Uxbridge Road. The first significant landmark is the junction with the A316, Apex Corner - not to be confused with its namesake in North London. Unlike its namesake, this one has grade separation for the A316 (the last junction London-bound - except the Hogarth Roundabout - to do so). It is also the terminus of the A305.
Beyond Apex Corner, the road continues first as dual carriageway until the A314 junction, and then as high-quality single again. A footbridge marks the divergence of the road leading to Feltham town centre (B3377) whilst the A312 bears right to cross in quick succession the A244 and A315. Beyond the A315, we become dual again on Fagg's Road, passing a number of trading estates. The reason for the large amount of light industry and lack of housing around here is readily apparent - NOISE - we are close to the end of one of Heathrow's runways.
This Google Earth air view shows the lost section of the A312 (Hatton Road) still visible as tarmac still on the surface or buried so shallowly that it shows as cropmarks in the airport grass. It was enclosed in the airport in 1948 or 1949. Its line is continued further south-southeast as part of the airport internal road Eastchurch Road. See this Wikipedia article. (On this lost part were two notable mansions: The Cedars, where Charles Dickens sometimes visited, and a woman who lived there inspired his character Little Dorrit; and Hatton Gore, where the botanist Kingdon-Ward lived.)
The current A312 deviates sharply to the right, along The Causeway and The Parkway, crossing the A30 Great South West Road and the A4 Bath Road at separate junctions close to their own convergence at the Henly's Roundabout. After the A4 (Waggoner's Roundabout) the parkway follows a sinuous course to meet the M4 at Junction 3. Because that junction marks the motorway's lane drop to D2M, the Parkway sees a lot of traffic avoiding congestion on the M4 at busy times.
The next section of the A312 through Hayes used to be very heavily congested, but since the construction of the Hayes bypass which opened around the end of 1991, it is a useful link to the A40. The bypass crosses the Great Western railway line and the Grand Union Canal on a long flyover, and also has a GSJ with the A4020. It ends at a roundabout in Northolt, where there is a connection with the A40 to the west near Northolt Aerodrome, at the "Polish War Memorial". This road was the B455, but because of the increased traffic generated by the A312 improvements, it is now the A4180. This roundabout marks the end of the diverted A312 and we are now back on the road's original line. The A312 here turns north eastwards, and we immediately notice a change in style, from quasi-rural 1990s to inter-war ribbon development.
We meet the A40 at the "Target" junction, and shortly afterwards cross the first of four almost parallel railway lines at Northolt station – this was the Great Western’s Birmingham line, although now only used by London Underground's Central Line. A little further on we reach a roundabout – the signpost for the left turn was missing when I was there so I blissfully went straight ahead, to find myself a dead end at Northolt Park station. Continuing by train did not seem an attractive way of getting to Harrow – the station only has one train an hour, on the Marylebone to High Wycombe route – so returning to the roundabout we find it is in fact a TOTSO. The A312 skirts to the west to pass under the railway, multiplexing with the A4090 to do so, before leaving it at another TOTSO to continue towards Harrow.
After passing South Harrow underground station, we note the grounds of Harrow School rising to the right, surmounted by a prominent church spire. However, after passing the junction with Roxeth Hill (A4005) we continue into the town centre.
Until recently the A312 ended at a totso with the A404 west of the town centre (the A312 being continuous with the London-bound A404). Remodelling of the town centre has resulted in this junction being replaced by a dumbbell arrangement, with one roundabout either side of the Metropolitan Line, and a new link road bypassing the town centre to the north which has been designated part of the A4005, rather than the more logical A312. Thus the last section of the A312, from Roxeth Hill to the A404 junction, is now a multiplex.
Original Author(s): Tim Lidbetter