The owners of Sheffield’s iconic Park Hill flats say security will be increased after arsonists set part of the 1960s brutalist structure alight.
A spokesperson for developer Urban Splash also confirmed work will begin on phase two of the multi-million pound development ‘this autumn’, but could not give a definitive date.
The fire began at 7.10pm on Monday outside the old Grace Owen Nursery School, in the part of the site earmarked for the next phase of development.
Crews from Sheffield Central, Elm Lane and Barnsley spent more than two hours tackling the blaze.
Firefighters had to check accommodation above the shop unit to see if anyone was inside as a precaution - but the site was empty.
A fire service spokesperson confirmed the blaze had been started deliberately.
Mark Latham, regeneration director for Urban Splash, said: “There was a fire just outside the old Grace Owen Nursery that was contained quickly by fire services.
“We are further increasing security and as we will be starting construction activity soon this will help prevent such incidents.”
Residents at the scene on Monday evening reported seeing three youths running away from the building shortly before the fire began.
In recent weeks, other residents have reported seeing people on the roof of the still derelict part of the site.
Mr Latham said the site was incredibly hard to police due to its size, adding the fire was located in a part of the site which is completely hidden from view.
The fire is the latest twist in a story which spans six decades of Sheffield history.
The development was built in the 1960s to house people from the area’s former slums, which were bulldozed to make way for the flats’ ‘streets in the sky’.
After falling into disrepair, it was Grade II-listed in 1998 before being bought by Manchester-based developer Urban Splash.
The long-awaited second phase of the regeneration was given the green light by Sheffield Council last year.
It includes provision for 200 flats as well as space for businesses along the ground floor.