The Triplet (Gasholder Nos 10, 11 and 12), King’s Cross

Summary

Three conjoined gasholder guide frames originally built in 1879 to 1880 (replacing earlier frames of 1861, 1864 and 1867) to the design of the engineer John Clark by the contractor Westwood and Wright for the Gas Light and Coke Company. Relocated from the original gasworks, about 300m to the south, following the expansion of St Pancras Railway Station when the gasholder tanks were buried or demolished and the bells destroyed. The guide frames were dismantled in 2001, restored by Shepley Engineers, and re-erected surrounding apartment blocks on the site in 2018.

Reasons for Designation

The Triplet, three conjoined gasholder guide frames originally built in 1879 to 1880 to the design of the engineer John Clark at the St Pancras gasworks, is listed at Grade II for the following principal reasons:

Architectural interest:

* the conjoined triplet of gasholder guide frames, designed as a structural response to the original cramped canal-side site, is thought to be unique in Great Britain;
* among the most aesthetically distinguished and finely detailed gasholder guide frames ever built, they observe classical architectural rules regarding the order and proportions of the columns, as well as the sequence of mouldings;
* for the visual drama of the three gasholder guide frames, originally built as the showpiece of the St Pancras gasworks during its Victorian zenith.

Historic interest:

* as a tangible reminder and physical manifestation of the St Pancras gasworks, which was at one time the largest gasworks in the country, and probably the world.


Group value:

* with the Grade II-listed Gasholder No 8 guide frame, of similar aesthetic distinction, and the Grade II-listed railway-side steam locomotive water point, coal drops and the Granary, as well as the canal-side lock keeper’s cottage (former pumping house); an evocative ensemble of former industrial buildings of considerable urban landscape value.

History

Gas lighting derived from coal was invented in the 1790s and from 1816 it took off in London and then spread nationally. Gasworks comprised coal stores, retort houses for the extraction of gas, plant to remove impurities, gasholders, and administrative buildings. The water-sealed type of gasholder was adopted from the earliest times, comprising a bell (gas vessel) open at the bottom and placed in a water-filled tank, so as to seal in the gas, rising or falling vertically according to the volume of gas being stored.

The Imperial Gas Light and Coke Company was established in 1821 and initially focussed on London’s suburbs north of the Thames. At first, the company employed the pioneering engineer Samuel Clegg as consultant and he advised that gasworks should be built along the Regent’s Canal, allowing coal barges to be directly unloaded to the coal stores of each gasworks. Gasworks were constructed at Shoreditch in 1823 and St Pancras in 1824. A design plan for the latter indicates that 12 gasholders were intended for the site. A detailed history of The Triplet and the site where it was built is given by Miele (1996 - see sources). In 1860 additional land was purchased to the north of Wharf Road (later called Goods Way) to allow for expansion; this land adjoined an area of poor quality housing originally developed by William Agar and the group of gasholders built upon it became known as the Agar Town station. In the 1860s the St Pancras gasworks continued to be the largest gasworks in the country, and probably the world, with a large number of retorts and two groups of gasholders built on either side of Wharf Road. However, in 1876 the Imperial Gas Light and Coke Company was amalgamated with the Gas Light and Coke Company. Staff numbers at the former Imperial gasworks at Fulham, St Pancras and Shoreditch were subsequently reduced. The St Pancras gasworks stayed active until 1904 but then closed with a subsequently brief revival in 1907 before it became a gas storage station with gas pumped from the Gas Light and Coke Company’s enormous gasworks at Beckton.

A triplet of gasholders was first designed for the St Pancras gasworks by the company engineer David Methven (Gasholder Nos 10 and 11) and his successor John Clark (Gasholder No 12) and built in 1861, 1864 and 1867 respectively. The contractors were Walter Mabon and Company of Manchester (Gasholder No 10) and Westwood and Wright (Gasholders Nos 11 and 12). The tanks were constructed by John Aird and Sons and built of stock brick and Roman cement. The largest had 16 piers set within the wall to take the columns of the guide frame and an upper rim of Greenmore or Bramleyfall stone. It was excavated to nearly 17m deep; possibly deeper than any previously constructed, and was of sufficient engineering interest that Samuel Clegg Junior published an account in his ‘Treatise on the Manufacture of Coal Gas’ (fourth edition, 1866). In May 1879 to September 1880, the gasholders were ‘telescoped’. This involved installing two lifts to the bell (possibly re-using the original lifts as the outer lifts of the new two-lift holders) and replacing the guide frames in their entirety by the contractors Westwood and Wright under the direction of John Clark. The columns of the new guide frames observed classical rules so that the lowest tier was in the Tuscan order, the middle in the Doric and the topmost in a simplified version of Corinthian, with the size and proportions also varying as classical canon dictated. The girders were constructed of wrought-iron instead of the cast-iron used in the Imperial Gas Light and Coke Company’s earlier holders at Bromley-by-Bow. At the centre of The Triplet was a triangular configuration where the frames joined through which a spiral staircase may once have risen (see Miele 1996, 22). In 1883 Gasholder No 8 (initially built prior to 1860 and now adjacent to the Triplet) was also rebuilt. All of the gasholders were originally referred to by their numbers and ‘The Triplet’ is a modern name adopted for the triple group of guide frames.

The Triplet and Gasholder No 8 were listed at Grade II in 1986. They were relocated to the current site from the original one, about 300m to the south, following the expansion of St Pancras Railway Station for the Channel Tunnel rail link. The tanks were buried or demolished, the bells destroyed and the guide frames dismantled in about 2001 and then restored by Shepley Engineers in their Yorkshire workshop. The Triplet was re-erected surrounding new apartment blocks designed by WilkinsonEyre architects at King’s Cross in 2018. The apartment blocks were built to varying heights, serving as a reminder that the gasholder bells in this position originally moved as they were filled or emptied of gas. The guide frame of Gasholder No 8 encloses a small park by Bell Phillips Architects and Dan Pearson Studio within which is a mirrored circular pergola; the reflections providing a kaleidoscope of views of the surroundings. The relocation of the gasholder guide frames were part of the wider King’s Cross regeneration project, following the decision to move the Channel Tunnel rail link in 1996. A masterplan was formed after several years of studies and public consultation, and in 2008 the Kings Cross Central Partnership was created between the developer Argent, London and Continental Railways and DHL. Located on the site of the former rail and industrial premises, including the Grade II-listed coal drops and the Granary, the redevelopment involved the restoration of historic buildings and the construction of new buildings. The 67 acre site included 3.4 million square feet of office space, 2000 new residential units, retail and leisure space, a hotel and educational facilities, as well as new squares and gardens, such as Granary Square, Lewis Cubbitt Park and Gasholder Park, forming a new public realm for Central London.

Details

Three conjoined gasholder guide frames originally built in 1879 to 1880 (replacing earlier frames of 1861, 1864 and 1867) to the design of the engineer John Clark by the contractor Westwood and Wright for the Gas Light and Coke Company. Relocated from the original gasworks, about 300m to the south, following the expansion of St Pancras Railway Station when the gasholder tanks were buried or demolished and the bells destroyed. The guide frames were dismantled in 2001, restored by Shepley Engineers, and re-erected surrounding apartment blocks* on the site in 2018.

MATERIALS: cast-iron columns and wrought-iron girders.

DESCRIPTION: the three conjoined column-guided gasholder guide frames, originally known as Gasholder Nos 10, 11 and 12, are to a largely matching design; all approximately 33m high but variously of 15 columns and 40.8m diameter (No 10), 16 columns and 44.3m diameter (No 11), and 13 columns and 32.3m diameter (No 12). They consist of three circular guide frames, each comprising three tiers of cast-iron columns joined by horizontal lattice girders (‘Type 15’ in Tucker’s typology of gasholders). The guide frames are conjoined at the centre so that several of the columns are shared by the respective structures. The columns observe classical rules so that the lowest tier is in the Tuscan order, the middle in the Doric and the topmost in a simplified version of the Corinthian. Each column supports an entablature bearing the correct classical sequence of mouldings; all rise to a cornice but the Tuscan order supports a plain frieze, the Doric a triglyph, and the Corinthian a frieze and then a dentilled cornice. The proportions of each column vary as the classical canon dictates; from the heavier Tuscan on the bottom to the lighter Corinthian at the top. The columns are made of shorter sections which are bolted together on the inside. The capitals and entablature blocks also conceal joints at the head of each tier. At the bottom of the lower columns are oval cast-iron plaques stating the date at which each gasholder was first erected and then subsequently telescoped. Attached to the inside edge of each column are the guide rails for the roller carriages upon which the telescopic bells of each gasholder originally rose (filled with gas) and fell (emptied). Several of the roller carriages have been retained and are adjoined to the guide rails close to where the frames are conjoined. The columns are linked together at the level of the entablature blocks by wrought-iron I-section 60 degree-triple-warren lattice girders, which are fabricated from sections of flat plate and angle that are riveted together. The southernmost gasholder guide frame also has rosettes on the latticework. At the centre of the cluster there is a triangular configuration where the lattice girders link the guide frames.

* Pursuant to s1 (5A) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (‘the Act’) it is declared that the following are not of special architectural or historic interest and not included in the listing: the residential apartment blocks and communal courtyard structure completed in January 2018. However any works which have the potential to affect the character of the listed building as a building of special architectural or historic interest may still require listed building consent and this is a matter for the local planning authority to determine.

This list entry was subject to a Minor Amendment on 21 April 2026 to amend the address

Sources

Other
Clark, J, ‘Volatile Heritage: St Pancras Gasholders’ in English Heritage Conservation Bulletin 42 (2002), pages 82-3
Miele, C, English Heritage Report: Gasholders Nos 8, 10, 11 and 12, St. Pancras Station, Battle Bridge Road and Goods Way (1996)
Tucker, M, London Gasholders Survey: the Development of the Gasholder in London in the Later Nineteenth Century (2000, Re-formatted May 2014)
Trueman, M, Gasholders: Step 3 Report for Monuments Protection Programme, English Heritage (2002)

End of official list entry

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