According to César Pelli, the most damaging criticism came from Prince Charles, who said on national television, "I personally would go mad if I had to work in a place like that".

His Royal Highness The Duke of Edinburgh officially opened One Canada Square on the morning of 26 August 1991,[26] and unveiled a commemorative plaque at the entrance to the building.

He spoke of the "large, airy space and clean, efficient office layout", as he declared the building ready for business.

The extension replaced the stainless steel columns, car parking spaces and road leading to Canada Square.

The pyramid roof is an important feature of the building, enclosing a maintenance plant and housing facilities for water supply and window washing, and an aircraft warning beacon.

[28] A louvre access door opens to allow a shining beacon to identify the building to passing aircraft.

[29] It is a permanent lighting of the One Canada Square pyramid using a thousand electronically controlled fluorescent tubes capable of sequence programming for special occasions and festive seasons.

The tower uses super-insulated windows at triple-pane glazing (with a high solar heat-gain coefficient), low-emissivity (low-e) coatings to prevent heat loss in winter months, UV coatings, scratch resistant outer layers, sealed argon / krypton gas filled inter-pane voids, 'warm edge' insulating glass spacers, air-seals and specially developed thermally designed window frames.

The only time when One Canada Square was fully evacuated was on 30 October 2001,[30] during a test drill in response to the 11 September 2001 attacks.

The test drill was unsuccessful as tenants were notified beforehand, hence evacuation was much quicker than expected by Canary Wharf Security.

Within 2 minutes, the access control system sends a memo to the Security Director itemising how many people have left the affected floor and how many remain.

They have woven steel cables called hoisting ropes that are attached to the top of the lift cabin and wrapped around the drive sheave in special grooves.

The international BREEAM standard has awarded One Canada Square for best practice in sustainable design and environmental performance for buildings.

One Canada Square energy performance has improved by decreasing 30% from 2007 to 2016 by initiatives such as installing LEDs and upgrading HVAC and water services.

The staircases in the four corners of the lobby leading down to the basement floor were originally embellished with a four-piece commissioned sculpture, The 20th Century–Thames by Keith Milow.

[37] Blade of Venus 1985, by William Turnbull, is on display, part of a series of bronzes that originated in the shape of Japanese swords and Chinese chopping knives.

[43][44] Notable works included: The ground floor lobby has a restaurant and bar, the current tenant is Shutters.

[45] The current office tenants according to Canary Wharf Group plc as at 30 June 2022:[46] The ownership of One Canada Square has changed since it was constructed.

There are normally ten maintenance personnel on-site during working hours and three at night to attend to routine repairs and adjustments to the internal environment.

[51] The research carried out by the BBC's Inside Out programme found that on midnight Sunday, One Canada Square left more lights on than any other building in London.

One Canada Square achieved the title of tallest skyscraper in the UK in August 1991 upon building completion (as of CTBUH guidelines), or June 1990 (during construction when it overtook Nat West Tower).

On 15 November 1992, the Provisional Irish Republican Army attempted to place a large improvised explosive device[34] near the tower.

The IRA had already worked out that to cause maximum damage, the bomb had to be placed under the Docklands Light Railway bridge to disrupt infrastructure near the Canary Wharf Tower for a devastating effect.

As the bombers were about to make their escape, security guards approached the van because it was parked illegally on double yellow lines.

As a result of this attempted bombing, the observation floor was closed (see Public access section) and security was dramatically increased at Canary Wharf.

[53][54] The towers at Canary Wharf were evacuated as a precaution following the September 11 attacks on the World Trade Center and The Pentagon in the United States.

[57] One plot was confirmed on 4 April 2008, when a terror cell appeared at Woolwich Crown Court accused of targeting Canary Wharf.

As the Canary Wharf Tower is the first skyscraper to be clad in stainless steel with metallised windows, this may have caused analog television reception interference for local people living in the area.

In the case Patricia Hunter and others v. Canary Wharf Ltd.[1997],[60][61] the House of Lords concluded there is no legal right to receive good television reception.

[62] Patricia Hunter and others lost the case because of a variety of reasons that included: In Spring 2001, the BBC received some television interference complaints from residents in the Poplar area[63] (north of Canary Wharf).