Nicholas Pawlik – a fellow architect who runs London-based practice Pawlik + Wiedmer – told the AJ he discovered the photographs when his grandmother Audrey, Smith’s widow, died in May at the age of 100. They had languished in the eaves of her house for the past 20 years.

‘They left all his stuff to me,’ Pawlik said. ‘There were some really early skyline studies of Sheffield, and those are definitely Ivor’s, and a development model of the first bit of the building. Ivor took the model shots.’

The photographs of the models are stamped on the back ‘CA Dept 1953’, presumably a reference to the city architecture department where, heavily inspired by Le Corbusier’s Unité d’Habitation in Marseille, Smith and his partner Jack Lynn worked up the famous streets in the sky development in their twenties.

It was built between 1957 and 1961.

One of the photographs – which are believed to have been taken by Smith himself – shows architectural models surrounded by exhibition boards. These boast that the scheme is ‘designed for children’s safety’ with ‘footpaths away from roads’; and explain that the deck ‘forms a continuous pedestrian street on every third floor’.

Another, understood to have been taken by Smith’s wife Audrey, shows Smith on the left, Lynn in the middle, and the city council’s chief architect, Lewis Womersley, examining an aerial model.

Ivor Smith (left), Jack Lynn (middle), and the city council’s chief architect Lewis Womersley, examining a model of Park Hill

Ivor Smith died in 2018, but Pawlik recalled that he’d relished the new lease of life given to Park Hill by its Grade II* listing in 1998 and the subsequent Urban Splash-led regeneration.

‘Ivor really enjoyed seeing how it had had the chance to fulfil aspects of the original vision,’ he said. ‘He grew up in an era of very aspirational council housing.’

Pawlik added that the final bill for the 1,000 flats was £2,360 per flat, or a total of £2.29 million, inclusive of fees. The modern equivalent would be £53 million, demonstrating remarkable value for money.

See Kunle Barker’s Opinion piece: Why Sheffield’s Park Hill estate is a model for our times

Annalie Riches, founding director of Mikhail Riches, will be talking about the technical, social, and design lessons of working on Park Hill’s regeneration at AJ Retrofit Live on 10 September.

Park Hill regeneration phase 2, Sheffield, by Mikhail Riches Architects