Tower 42

The tower's shape has been compared to that of the logo for NatWest, although its architect Richard Seifert always denied the similarity.[6][7]

Simplified plan and dimetric projection showing the shape of the top of Tower 42

The National Westminster Tower's status as the first skyscraper in the city was a coup for NatWest, but was extremely controversial at the time, as it was a major departure from the previous restrictions on tall buildings in London. The original concept dates back to the early 1960s, predating the formation of the National Westminster Bank. The site was then the headquarters of the National Provincial Bank, with offices in Old Broad Street backing onto its flagship branch at 15 Bishopsgate.

Early designs envisaged a tower of 137 metres (449 ft); this developed into a design with a 197-metre (646 ft) tower as its centrepiece, proposed in 1964 by architect Richard Seifert. The plan attracted opposition, partly because of the unprecedented height of the design and partly because of the proposed demolition of the 19th-century bank building at 15 Bishopsgate, which dated from 1865 and was designed by architect John Gibson. Seifert, who had developed a reputation for overcoming planning objections, organised an exhibition in which he presented two alternative visions: his preferred design, and a second design featuring a 500-foot (150 m) tower with an "absurdly squat" second tower alongside. Visitors were invited to vote and overwhelmingly chose the single tower design.[8] The final design preserved the Gibson banking hall and the tower's height was reduced to 183 metres (600 ft).

NatWest Tower during construction, viewed from Bank junction, c. 1974

Demolition of the site commenced in 1970 and the tower was completed in 1980. The building was constructed by John Mowlem & Co[9] around a huge concrete core from which the floors are cantilevered, giving it great strength but significantly limiting the amount of office space available.

In total, there are 47 levels above ground, of which 42 are cantilevered. The lowest cantilevered floor is designated Level 1, but is in fact the fourth level above ground. The cantilevered floors are designed as three segments, or leaves, which approximately correspond to the three chevrons of the NatWest logo when viewed in plan. The two lowest cantilevered levels (1 and 2) are formed of a single "leaf"; and the next two (3 and 4) are formed of two leaves. This pattern is repeated at the top, so that only levels 5 to 38 extend around the whole of the building.

The limitations of the design were immediately apparent - even though the building opened six years before Big Bang, and so there was less of a requirement for large trading floors, the bank decided not to locate its foreign exchange and money market trading operation ("World Money Centre") in the tower; the unit remained in its existing location at 53 Threadneedle Street. Other international banking units, such as International Westminster Bank's London Branch and the Nostro Reconciliations Department remained at their locations (at 41 Threadneedle Street and Park House, Finsbury Square, respectively) due to lack of space in the tower.

Innovative features in the design included double-decked lifts, which provide an express service between the ground/mezzanine levels and the sky lobbies at levels 23 and 24. Double-decked lifts and sky lobbies were both new to the UK at the time. Other innovative features included an internal automated "mail train" used for mail deliveries and document distribution; an automated external window washing system; and computer controlled air conditioning. The tower also had its own telephone exchange in one of the basement levels – this area was decorated with panoramic photographs of the London skyline, creating the illusion of being above ground.[10]

Pre-construction model of the NatWest Tower, including concepts that were eventually abandoned, on display at the London Science Museum

Fire suppression design features included pressurised stairwells, smoke venting and fire retardant floor barriers. However, at the time of design, fire sprinkler systems were not mandatory in the UK and so were not installed.[10]

The cantilever is constructed to take advantage of the air rights granted to it and the neighbouring site whilst respecting the banking hall on that adjacent site, as only one building was allowed to be developed. For a time it was the tallest cantilever in the world.

National Westminster Tower entrance forecourt in 1981

The NatWest Tower's viewing gallery at Level 42, as seen in 1981. This area is now in use as the Vertigo 42 champagne bar

Upon completion, the tower was occupied by a large part of NatWest's International Division. The upper floors were occupied by the division's executive management, marketing, and regional offices, moving from various locations in the City of London. The lower floors were occupied by NatWest's Overseas Branch, moving from its previous location at 52/53 Threadneedle Street.

The full floor configuration was as follows:

The adjacent annexe building at 27 Old Broad Street was occupied by NatWest's Overseas Branch cashiers and foreign notes and coin dealing operation.

In 1993, NatWest had planned a major premises relocation that would have seen the International Banking Division move from the tower and be replaced with its Domestic Banking Division, enabling the bank to terminate its lease of the Drapers Gardens tower. These plans had to be abandoned after the tower was damaged in the April 1993 Bishopsgate bombing, a Provisional Irish Republican Army truck bombing in the Bishopsgate area of the City of London. The bomb killed one person and extensively damaged the tower and many other buildings in the vicinity, causing a total of over £1 billion worth of damage to the area.[16] The tower suffered severe damage and had to be entirely reclad and internally refurbished at a cost of £75 million.[17] (Demolition was considered, but would have been too difficult and expensive.)[18] The external re-clad was carried out by Alternative Access Logistics with the use of a multi-deck space frame system to access three floors at once with the ability to move up and down the whole building.[19]

On 17 January 1996, during the repairs and possibly from the welding being undertaken, a fire started at the top of the building.[20] Five hundred workmen were evacuated and smoke was seen coming out of the top of the building.[20] A helicopter using thermal imaging equipment pinpointed the source of the fire, which was on the 45th floor in a glass-fibre cooling tower.[20] After refurbishment, NatWest decided not to re-occupy and renamed the building the International Financial Centre, then sold it.

East-facing view from Vertigo 42

Previous owners, UK property company Greycoat, renamed it Tower 42 in 1995, in reference to its 42 cantilevered floors. It is now a general-purpose office building.

Night view showing lighting display

A close view of the lighting system

In June 2012, a Capix LED multi-media lighting system was installed around levels 39 to 45. This replaced the previous high-energy floodlighting at the top of the building. The lighting system forms thousands of pixels mounted on a chain netting that is affixed to the surface of the building. Each pixel is formed of three RGB LED units, allowing a variety of lighting designs and colours to be displayed. The system was designed by SVM Associates and Zumtobel.[21][22]

The display featured the Olympic Rings during the London 2012 Olympic Games and the Paralympic Agitos during the London 2012 Paralympic Games.