Before 1994, Holborn was the northern terminus of the short and little-frequented Piccadilly line branch to Aldwych and two platforms originally used for this service are disused.

This was due to planning regulations imposed by the London County Council which required the use of stone for façades in Kingsway.

[10] The station entrance and exit sections of the street façade were constructed in granite with the other parts of the ground and first floors in the same style, but using Portland stone.

[10][21][failed verification – see discussion] The rest of the building above first floor level was constructed contemporaneously with the station.

Access to the platform levels of the station was provided by trapezium-shaped electric lifts manufactured by Otis in America.

[10] Although the station was constructed where the GNP&BR's tunnels crossed those of the Central London Railway (CLR, now the Central line) running under High Holborn,[c] no interchange between the two lines was made as the CLR's nearest station, British Museum, was 250 metres (820 ft) to the west.

[27] [10] The street level interchange between the GNP&BR and CLR involving two sets of lifts was considered a weakness in the network.

[10] The station frontages on Kingsway and High Holborn were partially reconstructed to modernist designs by Charles Holden with the granite elements replaced with plain Portland stone façades perforated with glazed screens.

[10] The lifts were removed and a spacious new ticket hall was provided giving access to a bank of four escalators down to an intermediate concourse for the Central line platforms.

[26] The station was redecorated in the 1980s, with platform walls lined with panels of enamelled metal forming murals designed by Allan Drummond that reference the British Museum.

At peak times, an additional train operated alternately in the branch's western tunnel from the bay platform at Holborn.

[32] Sunday services ended in April 1917 and, in August of the same year, the eastern tunnel and the bay platform at Holborn were formally closed.

[33] Wartime efficiency measures led to the branch being closed temporarily on 22 September 1940, shortly after the start of The Blitz, and it was partly fitted out by the City of Westminster as an air-raid shelter.

Again it survived, but the service was reduced in June 1958 to run only during Monday to Friday peak hours and Saturday morning and early afternoons.

[38] In the aftermath of the King's Cross fire in 1987, the Fennell Report into the disaster recommended that London Underground investigate "passenger flow and congestion in stations and take remedial action".

[46] On 21 October 1997, a 9-year-old boy, Ajit Singh, was dragged to his death after a toggle on his anorak was trapped in the closing doors of a Piccadilly line train.

[47] The disused branch line platform and other parts of the station have been used in the filming of music videos for Howard Jones' "New Song", Leftfield's "Release the Pressure", Suede's "Saturday Night" and Aqua's "Turn Back Time".

[52] Patrick Blackett (who won the Nobel Prize for his discovery of the positron), developed plans to install a cosmic ray detector on an abandoned platform of the Holborn Station following a row with his mentor Lord Rutherford at Cambridge University.

This was the only part of London with an underground tram system, and Holborn tramway station (named Great Queen Street when first opened) is still extant beneath ground, though with no public access.