The upper level walkway was begun in 1957/58 at the same time as the Shell Centre. It had shops beneath it, overlooked a square and the Torsion Fountain. The walkway was in use before before the Shell Centre opened.
Early publicity pictures from Getty’s show it in use on 1 January 1961. The new Getty layout has few details – the date was on the old site layout as this screencap from Google’s page cache shows:
Source: Getty Images
The walkway has been out of use for years, however at its most extended limit it reached almost to the Royal Festival Hall via what was very much a temporary structure, as shown below:
In turn it linked with a series of other high level walkways to the rear of the Royal Festival Hall that are also now no longer extant.
The section to the Royal Festival Hall fell out of use during the early 1990s, long before the London Eye was built. The remaining stump to Belvedere Road stayed open a bit longer.
Attempts to reinvigorate the walkway for the London Olympics in 2012 fell flat when the plans for redevelopment of the Shell Centre were speeded up.
Perhaps the walkway had something of an unsavoury nature – as is usually the case with such things. View from a Mirror, a cabbies London blog, tells us a pensioner was murdered on it in August 1973.
New proposals were submitted in January 2013 advocating demolition of the remaining sections of walkway.
This screencap from Googlemaps shows what things looked before the walkway was demolished, with the new but short-lived modern stairwell at the Belvedere Road end:
The above picture shows the demolition of the walkway, beginning with night road closures on 7th October 2015 to remove the section strung across Belvedere Road…
Few noticed the demolition of the walkway but at least one Twitter user did!
The fountain, the Torsion Fountain by Franta Belsky was also known as the Shell Centre fountain. A bronze sculpture which scoops water from one level into the next. It still remained on site during 2015 surrounded in scaffolding. At the time of writing it has vanished. Presumably it will return, incorporated into the new development?
The Torison Fountain by Franta Belsky with the old walkway behind.
April 2016 much of the demolition work around the Shell Centre had been completed. This short section of walkway across York Road in Waterloo still remained at the time.