It is a transformation that will turn Arthur Scargill's folly into a bustling hub of offices and bars in the middle of Sheffield.
The extensive revamp of the disused National Union of Mineworkers headquarters, on Holly Street beside the City Hall just off Barker's Pool, is reviving a corner of the city centre that had become a sorry eyesore.
Commissioned by the miners' leader Scargill when he moved his staff from London to Sheffield, the HQ was used for just four years from 1988, leaving it empty for a quarter of a century until a firm plan was made for its future.
There have been delays, but progress on the big overhaul is swiftly being made. Anyone passing the site this week would have seen builders hard at work and lights on in the upper levels - poised to become 14,000 sq ft of Grade A offices for Grant Thornton, one of the largest accountancy practices in the Sheffield City Region.
On the ground floor three bar units have been taken by Caribbean-themed venue Turtle Bay - which, in a reassuring mark of confidence, is already open and trading - along with Pitcher & Piano, set for an October launch, and an as-yet-unnamed operator.
The £5.5m renovation is being led by Barnsley-based developer Quest Property, part of the Brook Group which has secured a 250-year lease of the premises and the adjacent car park from the NUM.
"It really is the missing piece in the jigsaw," says Alexis Krachai, chief executive of the Sheffield Property Association, of which Quest is a member.
The Star is focusing on the mission of the SPA – which aims to be the ‘collective voice of property in Sheffield’ – through a series of features looking at major ventures. In each case, members – a diverse 46-strong group including developers, both city universities, planning consultants, solicitors and agents – are contributing in a professional capacity.
The NUM building's revival could be likened to a miniature version of Heart of the City II, the council's mixed-use regeneration project.
Supporters suggest it will consolidate a 'critical mass' of offices and leisure facilities in the city centre - HSBC is moving to Charter Square, the British Business Bank was the first tenant of the spruced-up Steel City House on Pinstone Street while Arup, Handelsbanken, BDP and Freeths are in 3 St Paul's Place.
“The development is breathing even more life into Barker's Pool," says Alexis. "It is great to see Turtle Bay doing well and providing another great choice for food and drink during the day and into the evening. More places to relax is great for those enjoying the many performances at the City Hall, as well as workers and shoppers."
He predicts the site will go 'from strength to strength', adding: "The site is one of the more prominent in the city centre. The development creates important links with Division Street, Devonshire Green and the new Heart of the City II."
There were several attempts to renovate the building during its long wilderness years, but each stumbled because it had a short lease which meant securing funding was difficult. A bid to have it listed also failed.
Today's scheme is being paid for through a collaboration between CBRE, the Sheffield City Region JESSICA Fund and Sheffield Council, which provided a £1.178m repayable grant from its Growing Places Fund.
"It’s important to remember this development would not have happened without the support of the city council and loans from the SCR Jessica Fund," says Alexis.
"This fund has been instrumental in helping to deliver a number of key developments across the city and wider region. It is a prime example of what can be achieved when the public and private sector work closely together.”
Inside the smoked glass and sandstone building, fittings and furnishings have been ripped out, but a four-tonne Italian marble frieze depicting mineworkers has been kept, partly because of its sheer heft, but also as a reminder of the site's heritage.
Architect Malcolm Lister was responsible for the original angular design, which reflects its period and has a prominent central section inspired by a colliery face worker's pick.
Unsurprisingly, it had a coal-fired boiler and the developer found a bunker full of the fuel when it took the building on. The once mighty union – which also occupied the former Sheffield Water Works Company offices next door, now a Wetherspoon’s pub – relocated to its current headquarters in Barnsley after its four-year stint on Holly Street.
In 2016 Matt Stephens, development director of Quest, said he could not think of another building in such a prime place that had stood vacant for so long anywhere in the North.
The company initially hoped to reopen it as a casino but had second thoughts. "It’s the most challenging project we as a company have dealt with. But we stick at things,” Matt said.
Conroy Brook Construction has been appointed as the main contractor and Grant Thornton alone will account for more than 120 jobs when it relocates from Broadfield Court by the end of this year.
“With the Grant Thornton name emblazoned across the front, and a 21st century interior designed to be open and available for all our clients, it will be at the heart of Sheffield’s vibrant future," senior partner Paul Houghton said when terms were agreed.