There are a few things that might cause people to wonder about the northern bits of the Northern Line. Why, for example, does East Finchley have two platforms that are never used?
Are those openings at the end of the platforms at Edgware meant to be tunnels?
What’s with the old station above Highgate?
And why does the single-track branch to Mill Hill East even exist?
The answer is that they were all part of an ambitious pre-war plan for the Tube that was never fully realised. The New Works Programme, announced in 1935 by the London Passenger Transport Board (the forerunner of TfL), aimed to rebuild several stations across the network, introduce new rolling stock and incorporate some suburban steam train services into the London Underground – all at the same time. The part which related to the northern ends of what was then called the Edgware, Highgate & Morden Line was known as the Northern Heights Plan.
In 1935, what would soon be named the Northern Line ran to Edgware on the north-western branch and a station called Highgate (not the present-day one) on its north-eastern branch. These two termini were (almost) linked by a railway line that connected Edgware with Finsbury Park; this was one of the lines that would become part of the Tube.
The line had problems, mainly the gradient which made it difficult for steam trains (despite various tunnels, cuttings and viaducts), while passenger numbers dropped when trams were introduced in some areas serviced by the line. It also didn’t quite fulfil its potential in terms of the suburban development that was expected to accompany new railways. The late Victorian period did see many new homes built along some parts of the line; for example, the parish of Finchley’s population rose from 4,937 in 1861 to 11,191 in 1881. However, the railway failed to trigger the development that might have been expected at its furthest point. Edgware remained rural, and was arguably changed more by the introduction of a tram service from Cricklewood in 1904.
What really turned Edgware from a small town in rural Middlesex to the North London suburb it is today was the extension of the Tube from Golders Green in the 1920s. A brand-new station opened in 1924, a new parade of shops was built along Church Lane (renamed Station Road) and streets of semi-detached housing quickly sprung up in what had been open fields. Census details reveal that the population of Edgware shot up from 1,516 in 1921 to 5,352 in 1931.
The expanding suburb, though, was built with the future in mind. The GNR’s original plans had allowed for a future extension towards Watford, and the building of the new shops across the road from the station allowed for a tunnel to run underneath them, while the streets beyond were laid out in order to accommodate a yet-to-be-built train line. It would be a decade before this could be put into effect.
Under the Northern Heights Plan, the line from Edgware to Finsbury Park, which after 1923 was run by the London & North Eastern Railway (LNER), would become part of the Northern Line. The Tube tunnel from Camden Town out to Highgate – which, in order to avoid confusion, was eventually renamed Archway – would be extended to the Highgate station on the railway line, reaching the surface just before East Finchley. Highgate station itself would be rebuilt as a multi-level station, with the surface-level platforms continuing to serve the line to Finsbury Park while the new underground platforms would link to Central London via Camden Town.
North of Highgate, trains from both the surface and underground platforms would run up to Finchley, from where they could go to either High Barnet or Edgware along the railway tracks which would be electrified so that Tube trains could run on them.
The other part of the Northern Heights Plan was that from Edgware, the line would extend into Hertfordshire to a planned new terminus at Bushey Heath (to be located at the A41/A411 roundabout), with additional stations at Brockley Hill and Elstree South. The intention was that, as had happened with Edgware a decade earlier, new suburbs would be built alongside the new line. The Northern Heights Plan wasn’t just adapting an existing line; it was about building a new one – and continuing London’s urban sprawl – as well.
It also required some stations to be rebuilt. Highgate was to go from a surface station to a multi-level one, and the architect Charles Holden, already noted for his futuristic Piccadilly Line stations, drew up plans which, if realised, would apparently have seen the station topped by a statue of Dick Whittington – a nod to the (probably apocryphal) story about the medieval Lord Mayor of London being summoned back to the City when he heard the church bells as he climbed Highgate Hill.
Holden also planned to incorporate local history further along the line, with statues planned for the stations at East Finchley (an archer, representing the area’s past as a hunting ground) and Elstree South (a Roman centurion, referencing Watling Street). Even the station designs were ambitious!
The redevelopment of Highgate as a multi-level station meant that the next station on the line, East Finchley, also had to be rebuilt to allow for trains to run south on two different lines. Holden therefore planned it as a four-platform station, with the two outer platforms serving the tunnel route to Highgate and the inner platforms the surface route. He went for an Art Deco design, while the sculptor Eric Aumonier was commissioned to construct the archer statue. Unveiled in July 1940, the Archer is almost twice natural size and has become synonymous with East Finchley.
As the date of the statue’s unveiling implies, work on the Northern Heights Plan had not (immediately) been curtailed by the Second World War, although blackout regulations did restrict work at night. Electrification of the High Barnet branch continued, and it reopened as a London Underground service in April 1940. The underground platforms at Highgate opened in January 1941 (they were immediately put to use as air-raid shelters), and for many years the newly-elongated tunnel was (via the Bank branch) the longest railway tunnel in the world.
The line between Finchley and Edgware, which had closed to LNER passenger trains in 1939 as a precursor to electrification, was only electrified part-way and that was just on a single line. The reason for this was that Mill Hill East station was needed to allow easy access to the nearby Army barracks which was the depot of the Middlesex Regiment, and as such a required destination for new recruits.
The work on building the extension north of Edgware had been a lower priority than electrifying the LNER lines that already existed, but some work had begun prior to the outbreak of war. The carriage depot at Aldenham had already been built, as had the arches that would support the viaduct at Brockley Hill station, and the tunnel at Elstree South had been dug. There had also been some work done at Edgware, such as the entrances to what would have been the tunnels under Station Road. That, alas, was as far as it got.
After the electrification of the line to Mill Hill East, work halted for the duration of the war. When it ended, the Northern Heights Plan had to be reviewed because new legislation needed to be taken into account. Specifically, the imposition of the Green Belt around London prevented further suburban development, which in turn destroyed the main reason for the extension out to Bushey Heath. It was abandoned, although it was depicted as ‘under construction’ on some 1940s Tube maps and not formally cancelled until 1950. Those parts of Edgware that were spared housing in the 1930s because they’d been ear-marked for a future Tube line have since been built over.
Electrifying the stretch between Mill Hill East and Edgware was still viable. However, the funding was not available as the extension of the Central Line (another component of the New Works Programme) and reconstruction of war damage were both much higher priorities. Somewhat controversially, Edgware and Mill Hill were deemed by the powers-that-be to have ample access to Central London already, and the direct link between the two branches of the Northern Line was scrapped; in its place, residents got a bus route between Edgware and Mill Hill East. The line continued to be used for freight until 1964, following which the tracks were removed. Part of it was subsequently buried under a new road called the M1, although other bits – namely the Copthall Railway Walk and the Mill Hill Old Railway – are now nature reserves.
The surface part of Holden’s Highgate rebuild was never realised. The old surface station continued to be used for passenger services run by the newly-nationalised British Railways between Alexandra Palace and Finsbury Park, although this was affected by coal shortages and passenger numbers declined. The service ceased in 1954, although the tracks weren’t removed until after freight services stopped in 1970. Today, the surface platform and some of the old buildings remain in place above the Tube station at Highgate, visible through the trees. The station building at Ally Pally is now a community centre. Further down the line, the platforms of Crouch End station, lost to the Tube, are still in place. The line now forms the Parkland Walk nature reserve.
With no surface-level passenger traffic heading south, East Finchley’s inner platforms were and still are only used for trains running between there and High Barnet, or for trains going to the Highgate depot. Services to Mill Hill East continue to run on the single line, albeit just as a shuttle service from Finchley Central outside peak times.
The entrances to the Elstree South tunnels were filled in (there is no evidence of these on the surface today), while the Aldenham depot became an aircraft factory during the war and a bus garage after it; it was demolished in the 1990s. The viaduct arches at Brockley Hill survived into the 1960s although only the bases remain today, visible from the A41 at the point where the (sub)urban sprawl of Greater London peters out into open countryside.
The Northern Heights Plan was definitely ambitious, and the part of it that did become reality – the High Barnet branch – remains a part of the Tube network today. The 1930s were a time when the people running the Tube were thinking big, and it took a world war to stop expansion in its tracks. With hindsight some of the post-war cancellations were arguably short-sighted, and as a result the small details that remain and occasionally intrigue – East Finchley’s extra platforms, the Mill Hill East spur, the Edgware tunnel entrances, the station above Highgate, what’s left of the arches at Brockley Hill and the nature reserves – all stand in their own way as monuments to what might have been. At least as far as the latter are concerned, the commuter’s loss really is nature’s gain.
T.F.T. Baker, J.S. Cockburn & R.B. Pugh (eds.), A History of the County of Middlesex: Volume 4 (Victoria County History, 1971)
Tony Beard, By Tube Beyond Edgware (Capital Transport, 2002)
David Bownes, Oliver Green & Sam Mullins, Underground: How the Tube Shaped London (Allen Lane, 2012)
John Glover, London’s Underground (Ian Allan, 2003)
Charles E. Lee, Sixty Years of the Northern (London Transport, 1967)
Colin & David McCarthy, Railways of Britain: London North of the Thames (Ian Allen, 2009)
G.F.A. Wilmot, The Railway in Finchley: A Study in Suburban Development (Finchley Public Libraries Committee, 1962)